Oh my goodness! The hall is full of people, i am up next to speak in front of the room, and my heart is beating out of my chest to the point that it may be about to explode! What do i do?
This happens to almost every public speaker- you are not alone. But you can take some steps to minimize this problem such as breathing more deeply and exhaling slowly in a way that is unnoticeable or you can tense your body parts one at a time and release them slowly. I would advise you to avoid coffee and caffeine or even cola as they can make your heart race even more. The point is to basically avoid coming into such a situation.
I know i say this a lot, but the solution to most of your problems is simply practicing in front of a camera. If you can record yourself and listen to a great and interesting speech from your own mouth, then there will be nothing or you to be nervous about. If your heart is racing, it should be because you are so excited to speak, not because you are scared and want to run away!