My most recent saves are gone.

Loldids  It sounds like the game is reading a different folder than the one that contains your current saves.  Here's how to find the correct folder:

https://sims4.crinrict.com/eng/2018/07/how-to-find-your-user-folder/

You can simply move your saves into the saves folder there.  But if you'd rather the game read the folder where your current saves are, please list its location as well as the location the game is currently using, as described in the link above.