i accidentally fucked my whole game

[Ducktard]

Could you go into more detail on how you managed to do this?

I Cant remember duck mate i was just messing around with the steam files ect in my libary and must of clicked something wrong...

I cannot confidentially give any fixes without knowing how this occurred, However, I recommend verifying your game's cache, If you don't know how to already you should go to your steam game library > right click garry's mod > properties > local files > verify integrity of game files... It may be a farfetched suggestion but it may work.