If you can't say it, but can put it in writing, do that. You are clearly one of the most articulate persons on this forum.

I used to go to a shrink with a long letter because I just could not talk. He was never surprised. I think it is not an uncommon thing to do. It was a great way to make the most of the session. I could spend days putting together exactly the right letter.

Don't despair! Keep your next appointment. Keep working on your issues.

Wouldn't it be boring to be a normal person?