My friends just kept wanting me to stand up for myself by repeatedly trying to trigger me
It sounds cruel, but is it working?
No... I know that I'm weak and I need to be stronger, but it's difficult. And I was annoyed after hearing their suggestions
You should try to tell your friends what you're thinking. It's good to know what really bothers you and is intolerable.
... I can't do it. I don't want to disappoint them by stating what I think.
You deserve to be able to get better on your own terms. Speaking up will only help with that, and your friends need to know your limits or they might unintentionally go too far. How would they feel if they accidentally hurt you when they didn't mean to?