So I play grounded on steam. Today, when I load my most recent save file (december, location at base near the pond), the file that load is the save file from august (location in broodmother den). The save files work just fine yesterday (dec, 25) but today(dec, 26) its not.

-Hello Im Noob

I'm sorry to hear that you've lost your most recent save and progress. I understand how frustrating it can be to lose progress in a game. If you or other players don't have a solution for this issue, please fill out a support request at https://support.obsidian.net/contact and include the following information: 

1. Platform (Xbox Console, PC Game Pass, PC Steam).
2. Multiplayer or Single Player Game (if multiplayer, can you tell us how many players in total in the game, and their platforms if known)
3. Description of issue.
4. Last thing you did in the game before the issue occurred, if applicable.

Thanks, and I apologize for the inconvenience that this has caused!