Xanax (alprazolam) may help but
Everybody gets nervous during presentations.
The more you do it the better you learn to deal with it. Do not look look at the public, look on top of their heads or talk to the wall you have in front of you. Get some summaries or important information written so you can provide factual information ( use power point or similar programs to make the presentation) they help 2 follow train of thoughts.