This is a longshot, but if you want try this :

- Start the game, and at the menu screen at the bottom left is a button marked player log.
- This will open up where all your characters and worlds are saved.
- copy all references to your world to a safe spot, as a backup.
- rename the world instances that have the .old extension and remove the .old from the file name.
- this should revert you back a save, and may have all your stuff.

dont forget to backup your files before trying to rename.