I am not officially diagnosed ASD but I think I probably have very high functioning aspergers like you do for many reasons.

Personally when I was younger I was more oblivious to my problems, especially in the social realm of things. As I got older I began to realize my problems more and more. It was a mix of slowly becoming aware of how society works and how I didn't fit in and also building up negativity about life because I wasn't succeeding the way other people were. At this point I am very pessimistic and negative about life in general. It can be easy to cope with mild ASD when you're a kid, before society places so many demands on you.

It's probably more like you've been thinking negatively for so long that you jump to negative ideas or conclusions when something happens. Like, not a neurological problem but your mind defaults to negativity because you've sort of programmed it to by thinking negatively over time and if you can begin to force yourself to think positively and optimistically it can be changed... like a thought process thing vs. brain thing. I don't know if this is how you're thinking of it or not or whether that is relevant but you can definitely move towards more positive thinking with effort and possibly therapy. If you have ASD you can fail a lot socially and it can make you fall into negative thought processes because you seem to fail when you are just trying to be yourself and giving it your "all" socially.

I've found that as I got older anxiety starting to set in very badly because it's hard to function and deal with having an ASD mind, even if it's pretty high functioning. It's hard to fit in and get by and anxiety and negativity can build up because you've had so many negative experiences by just following your social instincts, which don't do well enough to get you by. Of course it's all a matter of how you define it, but the way I was raised I was supposed to try to be "normal" and wasn't really taught being "different" was okay in a meaningful way and anxiety built up as a result. So in my teens I developed bad social anxiety and eventually had pretty severe panic attacks (got really bad around 19-20 and I had a bit of an emotional breakdown about when I turned 21).

My point is that maybe the anxiety and panic you're developing is causing the feelings of overstimulation. Maybe it's not the ASD itself, but secondary symptoms you are developing as a result of ASD. If you had pronounced classic ASD overstimulation problems (which I didn't and is not a necessity for having aspergers or HFA) then it might have been more noticeable when you were young.

I was "okay" for a long time and eventually had a breaking point where I basically lost it. My anxiety and panic had been building for months before and then I kind of cracked under the pressure. I did have sort of a "psychotic episode" in a way because I was really dissociated and things seems unreal and I felt disconnected from reality but certainly not in a "voices talking to me" kind of way.

Anyways I hope that was maybe helpful in some way. I don't mean to sound more knowledgeable than your psych because I'm NOT. I think you're positive thoughts are being blocked in a way and taking SSRI's could probably really help you think more positively. But it's not like a brain problem where your positive thoughts can't get through - they can if you train yourself to think more positively and therapy can probably help a lot.

Thanks for reading my post too. Maybe I used my response to vent about my own problems a bit but I hope it relates to your problems and that it was helpful. Take care