Sounds pretty scary! Ever since my stroke seven years ago, I've had some very brief sensations of lightheadedness, but haven't lost consciousness.

Still, I share your hesitation about seeing doctors. I've gotten some pretty mixed medical advice. I spoke about this in my YouTube episode, "Advice, Good and Otherwise" (approx. 6 minutes):

That being said, if I was actually losing consciousness, I'd see a doctor, pronto.