It isn't sea sickness, it is motion sickness. Getting motion sickness from playing video games (especially first person) is relatively common. Unfortunately there isn't a whole lot of options for treating this kind of motion sickness other than taking breaks or not playing games that cause it at all. No medication is recommended. Motion sickness is the worst with KF because you can't really take a break during an hour long game ... Which has caused me to be physically ill at least once this past year.