@Allyoopa Is it possible that you have OneDrive enabled, and your game folder keeps getting uploaded? If TS4 can't find its game folder in Documents (which it wouldn't be able to do if the folder gets moved to OneDrive), the game will create a new folder with no content in it.
If this is not the case, and your TS4 folder is in Documents\Electronic Arts where it belongs, perhaps this folder is itself corrupt. You can drag it out of Documents and onto your desktop and then launch the game again. Then play for a bit and save your progress; the save will land in the clean folder that just spawned. Quit, reload, and see if that save is still there.
If these approaches don't help, it's probably best to ask the TS4/Windows experts. (This is the mac section.) You'll get a more thorough response in the technical issues section, and your post might be moved over there.
https://answers.ea.com/t5/Technical-Issues-PC/bd-p/The-Sims-4