I just came out of a meeting where we were standing for about an hour. I got kind of warm during the meeting and took off my sweater. At about an hour into the meeting, I got this queasy feeling and started getting light headed. I left and headed to the bathroom and saw some black spots in front of my eyes. It really freaked me out because I'm only 21 weeks along. I had eaten second breakfast about an hour before and I had already drank 16oz of water this morning.

Has anyone else experienced feeling lightheaded or queasy (not from morning sickness) or even blacked out while pregnant?