I have a big presentation coming up next week at work. I can't mess this one up, since it happens on a big event in my organization. 

Whenever I present something, my heart pounds and my voice shakes terribly to the point where I can't speak at all. I pause awkwardly several times. I don't want this to happen this time. Please suggest any medication that would alleviate the anxiety and reduce the physical during that 1hr presentation. I heard that Propanolol works. I was prescribed this 9 months ago, but never actually tried. 

TIA.