I have to do a presentation in front of class...?

I'm so nervous, ever since I got the news I've been having butterflies in my stomach. I have a lot of weird symtoms when I'm in front of a crowd like, I have butterflies so bad I seriously feel like I am going to puke (one time I almost did when I was in 2nd grade) and you can literally see me SHAKING! My teeth chatter (like when your cold) and I feel goosebumps on my thighs, arms, and face. I talk EXTRA quiet because if I speak loudly, my voice sounds like I'm gonna cry. I'm so shy and in my class there's A LOT of people. I'm so scared!!!