Performing a monologue soon and I feel like throwing up my insides (new here).

[LittleGirlLost]

I'm taking a Diploma in Performing Arts in college, I love acting and it's my career goal. In two days I have to perform (for GCSE) a monologue that I've been looking at for only a few measly days. I've learnt the lines better than my own name thanks to my sort of photographic memory and have practiced it to death BUT I cannot stop feeling this constant dread, as if I'm about to go skydiving, and I just don't know how to handle it. It never used to be this bad but because my class is full of very unsupportive teenagers who hate me and talk behind my back, I'm just so afraid to do it. I've performed many times, a few months ago I had no stage fright whatsoever (hell, I performed a different monologue to a hall full of parents and sang in front of them too), but now it's hit me around the face and even now I feel HORRIBLE and when I get nervous during a performance my legs shake and I mess it all up.

I simply refuse with all my soul to let my feeling get in the way of my acting, I will throw myself on that stage even I start to cry but I don't want to do bad. Any ideas how to calm down?

BTW I don't have counselling and I'm not I medication and my own mother doesn't understand how I feel. I'm alone.