Yes, your doctor named it well. And it often happens to me in situations such as you describe -- you're tired, you're in front of an audience..and if it happens once, you get tense, and that's almost a guarantee that it will happen again.
Only thing I've ever done is slow down, think before I speak, and speak slowly. I'm sure some of the others will have more helpful advice. And of course, let your doctor know if it seems to be increasing.