What Causes Dizziness And Tunnel Vision?

Hi, I was at a club last night and had a few drinks, had a slight buzz and sat down to talk with a friend and have a few hits of his joint. I started feeling lightheaded with tunnel vision and within a minute, I suddenly fainted. I was told my jaw was locked up and my eyes rolled to the back of my head. A few minutes later, I was fine. This has happened to me once before, also after smoking weed. It was the same progression. I don t have a history of low blood pressure or fainting. It is a little concerning because I haven t had any issues before and I ve never seen it happen to anyone else.