So I just updated my Minecraft Launcher, and upon logging in to my world I found it was a restart in the same seed. I logged into my other worlds and found all my work had been reset. The date it said I started my worlds was today's date even though I started them in the summer. Does anyone know how to fix this problem?
Use a backup. If you have no backups available, or if they too are compromised, you are simply out of luck and must start over. This is how any type of undo/rollback feature works in any software, the way computers in general are designed you simply do not have the ability to go back to an overwritten state without a backup.