All files in saves folders have been lost after an update

Okay, so my computer has all of the requirements for Sims 3, I've been playing it for years on this computer. I installed a patch today and went to play for the first time in a while, but all my saved files were gone. I quit the game and went to my Saves file and it's empty as is all my content folders like saved outfits and screenshots. I then went to check my trash can and none of them were in there. No one else has access to my computer and I've done some searching and I can't find the solution to this problem. 

I wouldn't mind too much if this can't be fixed but I'd like to know what went wrong and why and how I can prevent it for the future.