Sounds like lack of oxygen to me. Ya dont wanna do that too many times.
I wouldnt worry about it, just make sure ya don't spend too long in confined spaces with other people using the same oxygen.
Reminds me of a strange incident I once had, I wasnt toking or drinking, just came home from work one day and as I was walking in my living room, all of a sudden, BAM! The floor came up and hit me in the back of the head!!
I bet I layed there for 15 minutes thinking WTF?!??