Ha, my thoughts get COMPLETELY random as I'm drifting off. I used to spend a lot of time daydreaming and I would continue my fantasies as I was lying in bed trying to go to sleep. As I got closer to sleep, my logical, formulated fantasy would get totally nonsensical and random and I would (haha) wake myself back up to continue the fantasy, only to have it go random again. I understand this to be exactly the way my brain is while I'm dreaming, so it always made sense that my mind's eye would lose rationality. Sounds like you are just maintaining consciousness as you enter sandman's land.