Shyness or Anxiety

Hi My name is Ciara and I was wondering if what I feel is shyness or some type of more serious anxiety issue. I think I have social anxiety. I have problem doing simple tasks like gettin tissue during class, or asking teachers to use the rest room even after they ask “does any one need to use the rest room.” I’d rather sit there for hours before I’d get up in front of the calss. Everytime I get delivery I order fom the same chinese restaurant because I can order online and I don’t like calling in orders. I have a fear that the person at the restaurant will get mad at me or I’ll mess up, and get confused while on the phone. And it’s sort of annoying because I’ve never been a fan of chinese anyway. I usually get a stomach ache after eating it. At lunch when we’re sitting with 4 or 5 girls that I am fairly familiar with (I’ve been knowing them 2 years now), I have things that I would like to say but I hold them in, and I find myself trembling at times. Close family whom I am myself with find me to be a very funny silly person, but whenever I have something to say at school, I rephrase n rephrase rephrase it so much in my head, that by the time I muster up the tiny bit of strength to say it, it’s no longer funny, nor really what I wanted to say. I have very low self esteem, but nobody believes me, they think that it’s fishing for compliments, when in reality it’s just that I don’t feel very good about myself. When I am around other girls I stay by myself n avoid eye contact because I feel inferior and they take it as I’m stuck up, so I generally keep to myself. I struggle ever day saying I am going to be myself at school, but I feel like there’s something holding me back. I feel like anything I do, will end in complete embarassment.