Game frozen on "walking backwards key"

The game seems to be frozen on the "walking backwards key" s. I play the game on the PC. Whenever I join a match, all my character does is walk backwards. I can still use my mouse and also ESC works but other than that I am always moving in the same direction. Also when I am in a menu it immediately scrolls down to the last option. 

Does anyone know how to fix this? (It only occurs in the game. Everything else works)

Thank you in advance!

Palorias