Think I had a seizure.

Yesterday, I was leaning against a counter waiting for my friend to get out of work, when I suddenly felt light headed and a little dizzy. I leaned my head down a little bit, figuring I was possibly going to pass out or something. ( I have fainted before, so I know what it feels liek just before) Only I didn't just faint, I passed out, fell to the floor, hit my head and my arms and legs were shaking for about 20-30 seconds. (says my cousin who was with me) When all this was happening it was like I was having a dream and was somewhere else, until I heard her yelling my name and felt myself shaking. I came to, stood up, still felt a little light head, but was fine walking to the car. This has never happened to me before, and I don't really like a lot of attention and didn't want people freaking out so I just said I was fine. I do have a doctor appt. set up for tomorrow. I have been looking up everything I can think of about seizures and what causes them. There was one thing I couldn't find a straight answer about and that was weather the use of marijuana can be an attributing factor. I had smoked a little bit that day, and was wondering if it could have caused it?