Can't reinstall Gmod?

I’ve been using Garrysmod for awhile and this is the first time I’ve had issues with it. For the past week or two I haven’t been able to play, I’d constantly get “This game is unavailable.” And yes, I did try the steam support. Because of all this, I decided to reinstall. So, I just deleted local content, and when I hit install, I get an error saying “The steam servers are too busy for your request.” And it doesn’t install.

It’s not a graphic’s issue since I use to run it with everything on High and AA on 6.

Having the same problem. Need help.