Black background and no input possibilities Mac

Hey!

I'm extremely new to Unity, and at the moment I'm using Unity 5 on my Macbook Air (just using OSX). For some reason, every time I press the play button (or just use cmd+p), Unity's background just goes black and I only see a scene menu and a game menu. Also, all input is blocked, so I don't get to change anything in the game or use any buttons. The only thing I can do is use cmd+p to get out of the playmode.

I really hope you guys can help me out, I'd really like to do something with making games!

Thanks in advance, Novalar