I don't know what these are but I feel REALLY weird sometimes. Could someone help me identify what this is?

Occassionally, during lessons I have these moments but I'm yet to identify what they are.

I'll suddenly feel very hyperaware of myself. My clothes, my face, my hair, the way I'm sitting, etc. And I start trying to imagine how I look to the others around me.

This is usually accompanied by feeling really ugly and annoying and feeling like 'too much'. So I'll go really quiet.

I'll also feel like I'm going to throw up (I know I won't throw up but I feel it) and I get these like pangs of sickness/nausea. My head feels like it might explode and everything around me feels like too fast and too much. Sometimes I can feel all these little patches of skin all over me that need to be itched as well as feeling each strand of hair on my head.

I'm not able to concentrate at all. Like I'll be taking in information but it doesn't stick around for me to understand it.

I'll often find a way to leave the classroom, usually by asking to go to the toilet.

Does anyone else deal with these? What do you do about them in the moment / how do you prevent them? Thank you!