I just had a look and I don't have a one drive account or anything so it can't be that. 7nfortunately I think this means all of my work is down the hole. :/ Thankyou anyway.
I am sorry to hear that. I've lost a few game saves when I was new to the game. It was devastating to say the least. After that I read up on all I could on saving backups of my saved games, households and houses so I wouldn't ever loose them again.
Something that maybe worth trying is to launch the game, create a new Sim and save the game. Go back to the Main Menu and press the Load Game button. Select a saved game. Mouse over or hover over the tiny folder under the game saves information. Like shown in the photo in the post linked below:
Sims 4 - Lost all Saved Game Data
This hopefully will give you an idea of where the game is saving your saved games.