Bugs glitches - unplayable

[Chiyu]

Hi !
There's something wrong with my skyrim or maybe PC ?
All games run fine and smooth.
Skyrim too but when i was attacking one of main cities when i was with storm guys something started to ♥♥♥♥ up. When i was standing sometimes i heard like my character was moving in water and swimming animation was turned on for a second. When i tried to take my weapon/spell in ready animation of getting sword was repeating many times when i tried to hit with sword i hit 10 times instead of 1 and my all stamina run out. Npc started to walk into walls.
Reinstalled whole game (downloaded not cd) and made new save. In tutorial mission this cart where u are riding with thief and storms leader there were many bugs like cart turning upside down or riding into a wall. Whats with this ? anyone can help ? ;(

[Chiyu]

Game is not crashing. it's just bugging. I'll download these mods to check out if this can help ;s (got all dlc's and no mods)