And I didn't die!
Today, I had my first-ever hot yoga class (75 minutes long) and, thanks to all your awesome advice, it was actually really good. I went in, fed and hydrated, and I never got nauseous or lightheaded.
I did take it easy during a couple of poses and sipped from my ice water as needed.
When I left, I was sweaty as all get out and not as glow-y as I'd like, but I felt good. HomeyHeart did laugh when I walked in the door because I had hair from hell and was beet red. I was also starving (is that normal?) and, after food, immediately napped.
Anyway, thanks to everyone for the wonderful advice! It made all the difference and I'm looking forward to next week's class!