I'm not the ass-kicker I thought I was

My husband and I had our first taekwondo lesson this past Saturday. My husband did surprisingly well. He finished the entire lesson. I, on the other hand, nearly passed out. I really almost passed out. We were doing a jumping exercised when my left ankle (which is the one I sprained last year) buckled and I fell. I got up and went back to the drill when I began to feel very light-headed. I sat down and realized I was on the verge of passing out because I started seeing starbursts, my hearing went out in my left ear and all the lights seemed really bright. The only reason I didn't pass out was because I sat down and put my head down before I had the chance. Anyway, I find it odd that I should nearly pass out after a similar sort of fall from the last time I passed out. I told my aunt about it and she said I should get checked for peripheral artery disease. I don't know what that is, but it seems obvious that if there's some sort of connection between me twisting my ankle and fainting, it started with the initial sprain. I'll call my doctor and find out if it's something I should be aware of. After I sat down for awhile and got my wits back, I finished out the class. I'm going to wear an ankle brace from now on. We have our next class tonight, so let's hope I can stay conscious for this one.