Oh my god, I was just doing that last week, and I didn't even realize it. I'd been invited to do a task that I very much don't want to do, but that I thought I really should do. I avoided accepting the task, and then when I did accept it, I started shutting down on all sorts of other things, feeling overwhelmed, although I didn't exactly have reason to feel overwhelmed.
But I felt what I felt.
Then I gave up; I just gave myself permission to not do the task and not care (too much) that some people are going to be disappointed/upset with me.
I immediately felt a weight lift off my shoulder, and then I went on to do some very good productive work that I'm proud of.
Looking back, I see that I've done this before; I'd just never thought about it much.
As a person with autism, I find this fascinating! The more you know, the more you know ...