Hmm...sounds simiar to something I experienced recently. I had been using ephedrine supplements to aid in my workout routine, and lost a lot of weight. However, all of a sudden, i had a weird lightheadedness, and almost passed out...with mild rhythm issues, which all returned to normal. I ignored it, and thought it to be a panic attack as I had no lasting symptoms at all. It happened again, this time with the ringing in the ear, which still exists in mild form, and took a few days to really get back to normal. I still felt better exercising, and had no endurance symptoms at all. Oh, and I am a 24 yr old male.
i would definitly get checked out-sounds more like a heart problem-whether from withdrawls or the ephedra itself at "our" age-lol never hurts to err on the side of caution-looks like we are catching up with the men in the heart disease area-hope you feel better soon-take care