Thank you for posting. A big thing to try to do, seeking help from a bunch of strangers. I"m sure it is going to be helpful to you.
While I can relate to your post, I don't have an answer. I do however understand the feeling of not wanting to do something without a seemingly rational explanation..
I have PTSD, depression and anxiety, though I'm mostly better now. This has given me all the usual symptoms that one would expect. My chronic anxiety would come the closest to your problem in that it meant among other things that I wanted to avoid some ideas or objects - for example movies with fire in them or mailboxes - it doesn't matter why in this context.
The point being that there was a set of reasons for my behaviors, and within my mind it was a set of quite understandable reactions to events in my past. It took me a while to figure out the mailbox problem, the fire one was horribly obvious.
I guess in your case there maybe something somewhere that has triggered this reaction. If it was something minor - like my mailboxes - then it might not be worth going into in depth. However this is not the case. From the sound of things it is a major disruption to your life and health. So it does need dealing with.
Although you said you talked to a psychiatrist you did not actually say if you are under treatment at the moment. Hopefully you are.
When I was first ill I just listened to what the health professionals said and assumed they knew what they were doing - a bit trusting perhaps. While there are tons of good ones not all meet a person's specific needs. Either that or they don't fully understand all the problems that need to be addressed.
Can I suggest if you are under treatment that in your next appointment you emphasize this problem and start discussing possible steps to help. If you don't think you can explain clearly face to face then do what I did, and write it all down, what happens, why, what the results are In terms of life disruption, time it has been going on, and anything else you can think of that might be relevant.
Hand the paper over in the consultation and go through it together.
If you are not currently under treatment then if you are like me you should be. I found there was no way I could soldier on alone. It took meds, therapy, self-help and family support.
Would you like to write back and say more, about your treatments, if any, your family situation and so on? There'll be care and understanding.