@kayetshana1 Try manually recovering the save(s), as described here:
https://sims4.crinrict.com/eng/2014/09/recover-backup-save-game/
Make sure to load these backups, if you have them, with no mods or custom content present, at least at first.
Please also see the first post of this thread for OneDrive-related issues:
https://answers.ea.com/t5/PC/CURRENT-ISSUE-Sims-4-saves-user-content-disappearing-PC/td-p/12475370
I don't know whether OneDrive contributed to your specific problem, but it's easy enough to check. And you might find a usable backup save on onedrive.com even after unlinking your computer.
