Sounds like a lot of this stems from you putting too much pressure on yourself to find something to do. I didn’t land on what my car was going to be until I went to uni at 21 and realised that I was enjoying the classes. I took a gamble on the course I picked and it worked out.
Sounds like you just need to go on a bit of a discovery journey and just try a load of different things. But don’t sweat it, don’t pressure yourself into trying to get into each one you try. Just try and go with the flow as much as possible and if something doesn’t click, start looking around for the next thing that might catch your eye.
I know it’s easier said than done, but I really do feel like a lot of this stems from the expectations you’ve given yourself (or that others have put onto you). You just need to chill, calm down and relax. It’s not going to be the end of the world if you can’t find something immediately. There’s always another entrance in if you just keep walking around. You’ll find the one you fit into eventually.
Sounds like you have body dysmorphia. You should really look for some help in dealing with that.
I don’t know how to fix that sort of stuff but I feel like if you at least understand that your own mind is sandbagging you constantly, it might help a little. Just remember it is not telling you the truth about how you look whenever you think like that.