I had this same thing happen to me and I have no clue what went wrong. I had 1/2 of a pot brownie before a concert with my fiancé and about 1.5 hours later we were in line, and I blacked out. I remember i was dreaming about the sky and my parents as I was blacked out. It was literally like I was at home asleep. Anyways, I don't remember anything after this point but my fiancé told me I passed out, and once they got me awake I stood up and passed out again. Then I couldn't get up or say any thing or make noises.. They had me laid sideways on the concrete pouring water into my mouth and over my head trying to snap me out of it. I remember hearing sirens but all I could see was black. I finally started to come through once we were at the hospital for an hour.