I am of no deep knowledge in the dharma but when it comes to your dilemma I can recommend some sources that helped me:

-Seeing that frees by rob burbea ( I think this one will really help) 
-The path to nibbana by david johnson ( To balance out nihilism)
-Losing Ourselves: Learning to Live without a Self by jay garfield
-Ulysses by James joyce especially the nora monologue
--Awake by angelo dillulo


For advice  : Dont be too hard on yourself.It may or may not last investigate and be with it. 

Hope this helps, take care  

What is your experience of "no self"?
IMHO The deletion of selfing processes that happens at paths builds up to the lessening of stress caused by the subconscious processes being hooked up to the fight or flight system.  If you have gotten to 1st path and started exploring second path there tends to be some issues from turning up the volume of thoughts; but if you are not in that area I would say it's something a bit different perhaps.

I would look into the feelings and thoughts that are creating this instead of just using the bucket of nihilism.

My first impression is that this could be Knowledge of Misery. That usually kicks my ass and puts me in a nihilistic phase much more than a philisophical bent from "noself" experience.
I would dig into the experiences of misery/depression more than trying to sugar coat it with no-self/impermenece/dukkha stuff. 
The better you can narrow down what is really happening the easier it might be to deal with in a normal way instead of a meditative awakening thing.
My marrage got distroyed because I misdiagnosed myself as having meditative problems when really I was suffering from good old fashioned depression with misery on top of that. Therapy and antidepressents did wonders to help me out but it was too late to save my relationship...just some thoughts.
(If you want to chat on the phone or vid send me a message)
Good luck,
~D

Nothing in Buddhism or the right view says "I don't exist." This is a common error that folks make, and yes, it's on the path to nihilism. What is discoverable is that there is almost always a self - it's just not permanent and doesn't define what "you" are. You are almost always creating a self, and having a self is necessary for operating effectively in the world.

So... buck up! You can observe the reality of your situation and overcome nihilism. You can see it as a false belief and the disastrous box canyon that it is.

Hello LJ

I am jottinng down some thoughts on the topic. All of this doesnt necessarily apply to you.

1. Anatta/Anatma/not self is an insight into the nature of how our experience regarding being an entity with continuity and control comes about. Through the practice of Anatta we get an experiential understanding that the sense of being an entity is just one more presentation of the mind, The sense of continuity is incorrect, the sense of control as ascribed to the continuously existing entity that we sense is flawed. This insight  has nothing to do with answering the question of is there or is there not a self. This insight tells us that any and everything that we can experience including the act of experiencing things does not contain a self. This insight gives us liberation from the stories that we create. The world has  meaning - thisis a story. The world has no meaning - this is a story. Eternalism - story, Nihilism - story. Everything that we can cook up either knowingly or unknowingly is just a story. This does not mean that stories arent important - they are! But the bone crushing weight that they carry drops off sharply. 

2. The insight into Anatma does cause fear to arise. But this fear is now seen as just fear. It isnt my fear!! Typically if someone structures their practice so that they build sensitivity to the mark of Anatta then as the insight deepens the mind moves on to become sensitive to fear, misery disgust, desperation. In a sequence. This is a flipping of the script in terms of the PoI map. This helps the mind to assimilate and learn from the dukkha nanas what it needs to learn faster, since the resistance is dropped

3. In terms of insight into any one of the 3Cs conceptual framing and languaging is often suboptimal. People say I will now do discernment of the 3Cs and they perhaps do it. But atleast some of them are scripting an experience - such is my speculation. The 3Cs are 'dhammas'. They are patterns that the mind starts to see in meditation and then the mind locks on to those patterns. This engagement of the mind with patterns and pattern recognition comes about by structuring awareness in particular ways and teaching it to engage with objects in particular ways. Basically exercises that we do in meditation. We learn these exercises algorithmically until they become native skills. At the time when they become native skills one can say - I will now do discernment of Anatta. If you are curious then check out this reddit post:

https://www.reddit.com/r/streamentry/comments/tucalw/vipashyana_geared_towards_the_quality_of_anatma/

I dont know how applicable or helpful the above may be to you. But see if anything is of use.

Regarding your particular problem of feeling horrible.
Lets just call it feeling horrible. Its a simpler description and closer to experience as opposed to connecting it to a philosophical position. This is the yogi way of being a vipashyana donkey I mean that as a joke . But it really is old school

In meditation do kayagata-sati. Mindfulness deeply immersed in the body. Beginning with a body scan. But instead of trying to deconstruct anything, try to suffuse the body with awareness. So beginning with a scope that comes naturally, zoom out and include more and more rather than less and less of the body. The end point should be the body dripping with awareness. Now do kayagata-sati specifically looking for sukha-vedana or everything that has  a positive valence within the body - sensations, aggregate body parts, the overall sense of having a body, The Fact Of The Meat!! Teach awareness to engage with anything that feels good in the body.

Off the cushion as you go about your day - try and stay connected to this niceness and softness and goodness where ever you may find it in the body. Let the mind go to everyday tasks of family and profession - thats fine. But if you see the mind go towards rumination and associated negative valence or feeling horrible then use that as a cue to connect to the sukha-vedana within the body. Again and Again and Again and Again .... ad infitum

Hope some of this helps.

Thank you all for your very kind replies, they helped me out a ton! For now I am just gonna stick to the practice I have been doing which is usually just 45 minutes of "look how its" noting which shargrol reccomended to someone in another log a while back. I do this practice out loud and I feel it creates quite a nice push and pull between the knower and the known. Since I have been doing this vocally there is almost no time for spacing out at all as I am noting 1-2 sensations every second or two. I am also doing my master's at UCL in london right now so I don't have much more time than this to spend on practice. Hopefully this is enoguh to get the job done!

I will also recommend reading Rob Burbea's book Seeing that Frees. It speaks directly on how to navigate nihilistic interpretations that come on the path. Beyond that, I think it might be time for you to really focus a bit more on jhana & samadhi. It's not a complete structural fix, but being able to put yourself in a remarkably pleasant and satisfying state more or less whenever you want is nothing to scoff at. Rob Burbea recommends at least doing half of your practice focused on samadhi with the remainder on developing the insight axis of the path. Maybe even some good old sila training would help too. Go do something good for yourself and the world, and I'd be willing to bet this will help out to some degree as well. 

Alternatively, if you've got the stomach for it, you can stare right into whatever nihilistic feelings, thoughts, or sensations arise and dissolve them with insight. Looking at them through the characteristic of impermanence might prove to be straightforward and helpful. "Oh no! It feels so nihilistic so often." *looks intently at the sensations making the nihilism* "Ah damn, those sensations flicker ever so often and come and go. Maybe I shouldn't have been so concerned. They make up such a tiny portion of my moment-to-moment experience."