Confusing EEG results. Help?

Alright so a few sundays ago, I got up out of bed (I had been laying awake for a while and decided to get up) and I get like how I normally get when I get up too fast ( I am a tall girl). I got ringing in the ears, my vision started to get black and spotty, and I got dizzy. But something else happened; I started to shiver, but I wasn't cold. I then fell down. I was conscience throughout; I was there for ten seconds, got up and felt fine. No head ache, no tiredness. I could talk throughout it, and I didn't have any complications.

Then I went to the doctor's and got an EEG done. They said that I had no seizure activity that was recorded, but they did say that the activity was comparable to that of an epileptic person.

I have smoked marijuana in my past.
I have migraine headaches.

Could it really have been a seizure? Am I epileptic? How can is epilepsy diagnosed? And could my past drug use/migraines be the reason why the reading was slightly abnormal?