Wow that sounds eerily familiar. I remember I was standing up and was sort of okay, and then all of a sudden I just became completely unaware of my surroundings and had to think about where I was. After that it really started to kick in and I kept getting the feeling of waking up. I remember trying to walk around thinking that doing something would keep me "awake," but it just made all the actions almost mechanical. Like moving my legs was automatic and I didn't know why I was doing it until I "woke up" again.