Skyrim bugs for me :(

Hey, as said in the title my game is going bonkers. For some reason whenever I look down everything stops working the way it should, for instance if I look down and walk backwards I start swimming up in the air and if I start a new game and look down while riding the carriage it and the other carriage start bouncing up and down the road until eventually the horse drawing the one you are seated in gets stuck in some stone and leaves its behind behind while the front of the horse spins around like a record.

I have tried playing it without mods and with low graphics but that didnt change anything.

Any help would be appreciated so thanks in advance.