Yeh the same just happened to me after an Origin update but i was already saving a copy of the TS4 folder whenever i exited the game in a Game Backups Folder also in Documents where the Electronics Arts and TS4 Folder is because i knew from what others have said the Saves are easily corruptible, and all it took was 1 day i relaxed on doing that the Saves were gone after Origin updates... but lucky i didn't do much since the last Save.
What you need to do is create a new Save As before you close the game then go into the Main Menu and always keep 2 in there... the new Save and the previous one and delete the old one... then Exit your game as you would, make a copy of the Sims 4 folder and paste it into the Game Backups Folder, then rename it just so it doesn't conflict with anything. Then next time this ever happens you can copy and paste the Saves into the Saves Folder in Electronic Arts > The Sims 4.
Yup! it works doing this because your game is all packed into the Save Files ;) but you cannot miss a day doing this because if it's not the Origin Updates it's the Updates for The Sims 4 that can corrupt the Save Files sadly.. the Saves can even corrupt on themselves for some reason.. so you have to keep a fresh Save and keep copies. Whatever that is about the game version file doesn't match with what happened with my game and i'm just Base Game... the update just simply erased the Save Files.