So i just bought the game and I enter just fine. However when i move my mouse to look around the camera is acting very strange. Firstly when i quickly look left or right the camera goes either up towards the sky or down towards the ground(while going in the direction i am looking aswell of course.) Also, the sensitivity of my camera seems higher when I am moving my mouse slowly and alot lower when I move my mouse more quickly. These disfunctions make the game completely unplayable and I would be greatful for any advice on what to do. Thanks.