I lost all my progress and it went back to my first family

Hi @rendezv0usg1rl

the most likely reason for this is that the game uses a different user folder then you think.

Here's instructions how you can find out which folder the game uses: https://sims4.crinrict.com/en/2018/07/how-to-find-your-user-folder/

If it's not the one your stuff is at, just move your stuff back to where it belongs. You might have moved it by accident.