When I try to play on my world's I open Minecraft to find that my world is just gone and can't find it anymore. This has happened for two of worlds now and has been going on for about like a few weeks. When I first saw it I was lucky because I had made of a copy of my world a few days back and didn't lose to much progress. I recently started a new world today and saved and quit while i went to go eat. I then came back to my world being completely gone