Yes, I definitely get stuck in thought loops. mostly thinking about social interactions that have happened.. how they annoyed me..
Randomly, i'll get a panic attack. i'll just feel super disgusted in myself and feel like never eating again because I feel "fat" but I'm not fat, so I never follow through with that

That rhymed, Lol.
and yes, i become very avoidant with everything when i'm stressed out. and then i get into negative thought loops about how i'm not doing what i'm supposed to be doing.
The anxiety feels like, I guess the feeling you get when you think you've forgot something, like leaving the stove on or something like that. I don't feel like I've forgotten something though, lol, just to make that clear. It's just the little feeling of panic and slight urgency you get that's equivalent.
i haven't learned to react positively to stress. i just know that I don't feel it whenever I'm distracted by something else, or done what I'm supposed to do, or just random little things that make me happy