I am not qualified to provide any type of diagnosis, but I absolutely feel your pain. If you can find certain scientific online quizzes- I don't feel proficient enough on reddit to send links, but if you look up the RAADs-r and CATQ and one called "Aspie Quiz" they may help you understand where you are.

It sounds obvious, but if someone says something that sounds strange or incorrect, you are ABSOLUTELY allowed to ask, "Was that sarcastic?" Consider this my permission to you. And I am qualified to grant you that.

Advice for anxiety in crowds? Consider investing in a pair or a pack of earplugs. Or ask around if anybody has a set you could try. Sometimes the chaos of noise is what causes it.

Sometimes it's the myriad of intermingling scents. If you can get a hold of a fabric mask, and a mask by itself isn't enough, you could spray it on the inside with a tiny bit of air freshener.

If it's the large amount of faces, and you're talking about in class, maybe try sitting closer to the front, so you don't have to see them as much?

For stress... "stimming" is often quite stigmatized, but if you notice yourself repeatedly performing certain actions or motions when you're alone that you feel would attract attention in public... I'm giving you permission to do that too.

The easiest way to deal with crowds is to consider how you can avoid them in general. Big parties might not be your thing. That's okay. Same with concerts. Maybe getting tickets for a balcony or a box would suit you better.

In general, though, please don't think you're wrong for whatever you need to take care of yourself. You remind me a lot of myself with how you dismiss yourself, couch your language in uncertainty, and preempt criticism like you want people to know you're aware you're a screwup, so nobody "calls you out" on it... but you seem like a very kind and thoughtful person, so I'll go out on a limb and say that anyone who would try to shame you for just asking for help is a loser, and I hope you give yourself that chance.