Black screen after champ select on MAC

Everything has been fine until later last night when I went to start a ranked game and when champ select was over I was brought to a blank black screen where I could see my mouse and move it but nothing came up. When I click you hear like the block sound on Mac and I can't tab out or anything. I have restarted my computer and it does the same thing. I can no longer receive loot and have bans and took 3 loses on ranked bringing me down a lot and it isn't even my fault. Please some tell me what's going on and a solution, this is really aggro to me