This is totally how I felt when I got back last December from CA. I kept saying that my brain was like a blank slate. I would be interested if anyone has further comments on this.
This sounds like my ickiest form of dissociation. I'm not amnesiac. But I am voided. No feeling, no thought, no connection to my surroundings. It's like my body is an empty shell and there is no person in there. Mind blank too. If I could get a brain scan on that situation probably very little is happening. It would seem I don't feel fear, but only because it's all too much...usually an undertone of threat but everything else goes offline. But even on good days I feel quite void of self sometimes. This isn't uncommon in BPD and complex or developmental trauma (like ongoing childhood trauma or severe early trauma). Not sure if that matches with what OP or you are saying @shimmerz ...hard to word this stuff!