Some things about what you describe resonate with past experiences I had with a (similar? identical?) state. In particular, this:
Persephone Hades:
In a past one, I became quite scared, as I felt like I was losing all cognitive reference points, including even the thought of a container (i.e. I am on a meditation retreat).
What helped me was to keep in mind that all of the worrisome things that could occur in the state I experienced were just markers that showed in what ways the state hadn't "fully expanded"...in other words, in the fullest version of that state, those things would not be there, and fears of dysfunction and things like that were just the last vestiges of 'me' sitting outside on the state and commenting on it as it happens.
One thing that definitely seems like 'you' commenting from the outside:
I go to a group interview and feel "why are you all talking?" because there is so obviously nothing at all to say.
So, I would suggest investigating with that in mind...and, at minimum, treating whatever worries or scary thoughts about dysfunction that come up as being what happens when this state co-exists with the everyday 'you', not a feature of the state, just a feature of the interaction between the state and 'you'.
Even this might fit in that category:
I am writing this post because my housemate feels no inclination to talk or write.
i.e. the lack of normal (behavioral) impulses, or the "stoned silence", might be what happens when half-in and half-out of the state.
Apart from that, may I ask for how long you've been practicing? I found (when doing concentration practices very early on) that it was easy to reach a state that was very...lacking in qualities. I could sit around afterwards and do nothing and not have a problem with it, not because I was content, but because I felt a sort of all-pervading "nothing in particular". On the other hand, behaving normally and interacting normally (even listening to other people talk) was effortful and annoying. Eventually this effect went away when I took up meditation more seriously...it's possible that in part it was merely some kind of experience of my mind adjusting to meditating (or to certain meditation practices).