glitches out at the end

After a match my client glitches out an i cant use my mouse anymore and i have to use the x out button on my keyboard to go to the chat after a match. what it does is puts my mouse in the middle of the screen and then anytime i try to move it, it just moves up and down really fast in the middle of the screen and i cant use my mouse outside if the game. please help, its less of a game breaker as it is inconvenient, but none the less annoying.