Is it possible to be hypoglycemic without being diabetic?

I don't have diabetes. I don't get sick when I eat too much or too much sugar or anything. But when I don't eat every 3-3.5 hours I get dizzy. I get really bad head aches that tylenol doesn't fix. My vision gets blurry and blacks out sometimes. I've fainted a few times. I also feel nauseous but I can't vomit. I'm 19 if that matters. My mom seems to think I'm hypoglycemic?