Pyke R and screen freeze

Before the weekend everything was fine. I played Pyke and my game was fine. I havent played a few days, didnt touch my laptop or league. Now when I play Pyke, and I ult, my screen freezes and the ultimate doesnt really cast, it does on my screen but other players do not see it. Then my screen freezes and after 1 second it becomes unfrozen and my ultimate is cast again, and this time it actually casts. But due to the freeze it misses quite a lot. This is not the case with any other champ, they work fine and never freeze my screen. I had this pyke R problem 3 games in a row, with almost every ult I cast, what could be the problem?