Some games give me motion sickness too but only intermittently. Playing in a better lit room may help, so your body is aware that it's a video game. Your visual input is telling you, I'm moving or spinning but your inner ear tells you I'm sitting still, call it your accelerometer or gyro position device. At least you don't crash like our POS devices.
My Forza 4 works again. I had to redownload (86GB) and reinstall.

