Red all over

Public Speaking is not my favorite thing. I know I am in good company. Much to my chagrin, I need to speak in front of groups of people several times of year due to my (former) job and my being a missionary candidate. So today and tomorrow are my lucky public speaking days, and it has been interesting already. I taught with another young lady from the school district today and I experienced the dreaded "free floating anxiety" that sometimes hits me even when I don't feel all that nervous.

I turn beet red, start to sweat, need to clear my throat and generally feel like I'm gonna die. Not my favorite. So this happened when I presented my first chapter of the text today, but after a short break between my first and second chapter my anxiety response was almost gone. Even if I try to calm down and don't feel super nervous, I can't break the cycle of anxiety while its happening. But give me a few minutes where the focus is off me, and I can usually pull it together and act like a normal person once again. Why is that? Does anyone else experience this?