Re: Sims Family disappeared and world state has reset.

@TaylorKate1998  I'm not sure whether you triggered this or the game had a hiccup.  The way you've described it, your data should still be intact.  Even if you'd somehow started a new save, the old one would still be present.

Anyway, please go into Documents > Electronic Arts > The Sims 4 > saves and look at the timestamps on all the files, including the ones that end in .verx.  These are the backups for a given save with the same number.  The goal here would be to find a backup save with a timestamp as close to the point where you lost the data as possible without going past it.  For example, if you noticed your save data reverted at 8 pm, you'd want to test the save from 7:45 before the one from 6:30.

Here's how to recover backup saves:

https://sims4.crinrict.com/eng/2014/09/recover-backup-save-game/

Please use the manual method—I find it's easier to keep things straight that way.  There's no harm in testing all of them.  But this assumes that you have an older save to revert to, and I'm not sure from your description whether that's the case.