Black screen

So yesterday I was playing ranked games. I had played two games and everything was fine but upon starting my third game after I briefly left for 2-3 minuets. When I came back my screen was black. There was no loading screen. One of my friends in game asked if I had disconnected. I checked but it still showed I was in game. I waited a few more minuets but it still stayed the same, just a black screen with just my mouse. I restarted my client over 20 plus times in the time period that the game lasted, and restarted my computer too. After that I left for 4-5 hours for work thinking it might have just been a bug. When I got back I made a custom game test if everything was alright or not but again the black screen showed up. I uninstalled league and re-downloaded it again. After that I tried once more in a custom game but again no loading screen just a black screen. I'm not sure if this is just my computer which is a MacBook Pro that i've had for 3 years. But i've never had this problem before. If it is a bug in league though how long will it be until it is noted and fixed? Please reply if anyone else is or has experienced this problem before. Thanks!