YCR, for better or worse, that sounds pretty normal.
A lot of classic dark night meditators go through exactly the kind of psychological/POI conflation as part of their practice. Just knowing that this can happen is step one and probably the most important step -- so many people are completely lost without knowing it.
The next steps involve really being with those expereiences/nanas and realizing that our mind states appear (at least initially) almost like we get psychological reborn into world where we are sad, angry, despair and it kinda occurs (at first) all at once and almost completely without reason. Although that sounds depressing, it also means that now the meditator can actually "see" the body-mind states AS BODY-MIND STATES --- which means they are somewhat separate from the knowing mind. In other words, without a meditation practice, we would just BE sad, angry, in despair etc.
The fact that you are noticing a ~weekly cycle and have reached a kind of "fuck it" stage is actually a good sign. At this point, you probably have realized that you can't "fix" or "run away" from these experiences. This is when every classic dark night yogi realizes "I can't go around these states, I have to go through these states".
The way purifications happen is by somewhat letting go of thoughts about these states and instead really looking at how it shows up in the body. Each time you fully experience a sensation, and urge, a feeling/emotion, there will be a little release --- but not if you are intellectually focused on thoughts about practice or thoughts about the sensation, urge, or feeling/emotion. The idea of progress of insight is when you have the complete knowledge of the nana, then you know how to accept the nana with equanimity and you move through the nana. So if you are very experienced at the Misery nana, when feelings of sadness/misery happen, you don't fight it, you don't run from it, you fully experience it as a body-mind state, and you "as the knower of the state" are not trapped by it, and so even though you are in the nana, you move through it with equanimity. Not an equanimity that is dull and unfeeling, but an equanimity that can go through all the challenging sensations of the nana and yet still feel like you are fundamentally the knower of the nana, not the sad/miserable person.
Therapy does a lot of similar work, which is why therapy and meditation together are perfect for dealing with the dark night stage. Therapy can also help when there is a past-trauma aspect to the dark night. In other words, sometimes there are old experiences of trauma that start being relived when practicing. But pretty much every human being will go through some aspect of dark night/purification because what practice is doing is expanding our maturity and sanity into a new stage, just like we went through when we were kids and growing up, and just like kids, there's a lot of frustration and anger and sadness and complaining etc. as we move through this next stage of development.
For meditation practice, you need to be clear that thinking about things really doesn't help much. Instead, you need to meet sensations at the level of sensations and really feel it. Same thing with primal urges and feelings/emotions. It's when they are experienced directly that the purifications occur. Basically, all of those feelings want to be felt and if they aren't fully felt, they will keep coming up.
For example, what are the sensations and feelings/emotions and thoughts that create "the deepest sadness in my life"? Most importantly, pay attention to the sensations themselves. How does my physical body feel? What sensations make up the feeling? Where are the sensations located in my body? Are there different sensations located in different places? Do the sensations move or seem to move or flow? Do the intensity of the sensations increase and decrease?
While you are doing this level of investigation, you might get a dismissive/angry feeling like "this is stupid, I shouldn't have to be doing something this stupid. I shouldn't have to be feeling all these yucky feelings. It's just wrong." And you will probably have all sorts of thoughts about "where am I in practice?" "which nana is this?" "is this really practice or is Shargrol just a bullshitter?" "I've already done this stuff, why do I keep having to do it?' etc. etc. etc.
The important thing is not to spend a lot of time on these feelings. Sure listen to them, notice them, just don't waste too much attention on them. Just notice that you are feeling ill will for the practice and you are having worried thoughts about practice. Totally normal, but just not super helpful. If we could move through this stuff by having emotions and thoughts about it, then everybody in the world would be enlightened because everyone in the world has emotions and thoughts.
So notice "ill will" and notice "worrying about practice" but then return to being curious about the sensations.
Here's what basically happens in purifications: all of these solid feeling sensations and urges are like sharp rocks in our body-mind, created as part of the normal process of being a feeling human. These sharp rocks grind against us when we experience certain things (specific to each person) in a kind of automatic way. But when we put our attention on the sensations of these sharp rocks, they start getting softer and more rounded. They behave almost like sharp pieces of ice in the sun. They soften and round and get smaller with attention. Many of the sharp rocks wind up melting away, turning into water and then turning into vapor and disappear. It's really amazing. It's what makes practice so incredible. After a year or two of really good practice, we can almost be different people -- not reacting to the stuff that used to make us crazy.
In the long run, what seems to happen is that many many many of the sharp rocks are realized to be not helpful and when they are fully experienced and showered with attention, they melt completely away. What is left behind are sort of the key feelings that we still need to be a human. We will always need some fear, some sadness, some worry in order to stay safe in this crazy world of ours -- so that essential stuff stays. But so much of our needless worry, paranoia, over-reacting, freaking out etc. goes away by meeting our experience at the level of sensation during meditation.
Anyway, my hunch is that you basically already know everything that I've already said, So I guess the only thing I can really add is a statement that "yes, making progress like this really is possible by a normal human! it just take time and sometimes some helpful advice from meditation friends and teachers".
For what it's worth, it can be good to describe the specific challenges you are working in your practice log. Very very specific, like what sensations and urges you are working on, that way people can give you targetted advice.
Hope this helps in some way!
