i know how you feel it’s my first year in highschool too and im going through the exact same thing,you’re not alone ❤️.

Mental breakdowns. No you feel nervous. Get a grip girlue

It sounds like you are struggling with anxiety. Of course, you shouldn't self diagnose, you should speak to your parents and/or a doctor. Anxiety can manifest as real physical symptoms and can be quite debilitating, but it can be treated.