Weird Black Screen Glitch

So I started a game of League and like 10 minutes in, my screen turned black, then went normal and my game exited full screen mode. (I am playing on OS X if that helps) Is this bug happening to anyone else, or is it one of those one time bugs? I could still play, but my HUD wasn't on the screen. I could hit F3 then move the position of where the client is, but then I couldn't see most of the screen! Did this happen to anyone else?