I'm 13 years old, almost 14. For a couple years now, I've had these yawns and streched that make my vision just leave and I feel blind. It isn't like all the other comments I see like "it looks like a fuzzy television thingy." This one time, I stood up, yawned and streched at the same time and I woke up on the floor and my dad in my face asking what happened. I apparently fell down and passed out. I've never passed out in my life and that was pretty scary. Is this serious? Or is this like a vitamin or mineral problem?