I do usually sleep on my back. Sounds like you have the same problem as me.Originally posted by: Slap
I have had the exact same thing for the last few years. It happens rarely......maybe 4 times a year. I think it is due to my sinus problems. It always happens when I am sleeping on my back. I think fluid somehow gets in my ear causing me to wake up with my head spinning but as soon as I raise up and focus it goes away. My head usually feels like a fish bowl for the next few hours and then everything is fine.I don't know, but I do. I'll wake up right out of a dead sleep with my head spinning around in circles. Usually if I stare at my clock intently the dizzyness will go away, but I'll still feel a bit odd for the next few hours.
As for the original thread topic, I found the problem. 3D Studio VIZ. All the rotating around was screwing up my head. Quite odd considering I have no other motion sicknesses at all. But after using VIZ for a few days my head adjusted and all my problems went away.