shaking so much

I can nearly get into a panic just thinking about when the NEXT time I have to speak might be. I've seen psychologists, psychiatrists, and blown a bundle of money, but still.....shaking, voice trembling, voice higher than normal. Have you ever seen some of those old movies with Don Knotts? It is just like that. Once I was volunteered to have my blood pressure taken before a group. My pressure was higher than what the machine was calibrated to measure!!! Yet, at home, I'm 120/75 or less. Whew!