Solved
Game updated and I lost all of my progress/ builds
I signed into the game and instead of my normal "sims are missing you" with a picture of the last sim I played as, I got NEW GAME. I played yesterday and everything was still there... I just finished...
@RaevenSkie If you moved the Sims 4 folder out of Documents > Electronic Arts, then yes, this would make your content disappear. Now that you've started the game again, a new Sims 4 folder has spawned with no content. So all you have to do is move your saves, Tray files, and anything else you want to keep from the old Sims 4 folder to the new one, and it should show up in-game.
