Headache/Nausea/Hot Flashes?

Lately I have been having these "episodes", where I start with a slight headache, and then it turns into me getting hotflashes, and becoming nauseous. I almost feel "not with it"(Can't think straight). I feel like I am about to faint, but never do.

When I was younger,my doctor had told me I was hypoglycemic. I have not worried about this because I have learned to have control of my sugar for years now. I eat many times during the day, so i am not sure where any of this is coming from.