Cannot left-click

The game does not recognize left-clicking. at all. I WISH I was exaggerating, believe me. I can't switch my items, I cant use skills or wards that aren't smart casted, I can't even navigate the shop the way Im used to. At first I thought my mouse was broken but no, this only happens during league play. Not even in the lobby, only during the game. I usually don't bother reporting the post-patch glitches because they're usually small and fixed fairly quick but this... I cannot play until its fixed. At all. This is the worst glitch I've ever seen, I mean... you can't click on anything! There's just no amount of compensating I can do to make up for the inability to use half my mouse in game.