Anyone ever get this?

I sometimes feel sick after a warm bath but recently something weird happened.
I was lying down in a hot bath (I mean really hot, so hot it almost feels cold) for about 20minutes, then I stood up and got that "Oh I stood up too quick" feeling. But it didn't go away, then my vision went all tunnel-y, I couldn't hear well, my balance was all out of wack and then..I threw up. :X

It was a cool feeling before the throwing up, but strange all the same. Any ideas? Was it just the heat and then the standing up too quick?

My blood pressure and all that are fine. I have to get a full medical done every year for my job so I know I have no obvious problems.