I definitely know your pain as I have the
exact same problem. I'm a Computer engineer and my dept. is about 10 people, all very smart senior people. I was able to get where I'm at without even getting my college degree but now I've moved up and am faced with the same problems as you. Speaking/presenting. Whenever I have to express my opinion in front of a group/audience I feel terrible, nervous, sweat, stammer a little. It's totally embarassing. I wish there was something to just turn it all off. Everyone else in my group seems like they actually enjoy getting up to speak.
It's so frustrating!!