OMG i hate that feeling like im going crazy. Happened to me once when i was laying in bed trying to fall asleep. I had such terrible racing thoughts, mind was going a mile a minute and i kept thinking i was on an island with all the people on LOST (as i had watched 5 straight episodes that day). Then id have to remind myself where i was then my mind would wander there again. It was so scary i hated it. I was also very disoriented I got so into my thoughts im not sure if i slept the whole night. Hasnt happened to me since but im always scared itll happen so most nights i gotta get real fucked up and drowsy to fall asleep unless i was really active that day and tired enough to pass out without racing thoughts.