my head starts turning from the inside and i feel tired its something that wouldn't happen to me before (some years) when i played cod 3 for three hours or so for example... i now got far cry 4 and I can't play for more than an hour! curse... is it a matter of habit? what do you think?
Motion sickness probably. Try sitting farther from the screen or changing the field of vision? Or take breaks often - just stare at something outside your window very far away. I used to get so nauseous playing Dirge of Cerebus on the ps2. Also Batman but I think that was more because the rapid switching between modes.