3 Worlds of mine have been deleted either while the game freezes while loading or while in-game even in the menu, the worlds are still intact in the minecraftworlds file, I'd LIKE to KNOW

why this is happening and if there is a way to restore my worlds, I am ABSOLUTELY tired of THIS bug., it has made me want to STOP playing because these are VALUABLE worlds. Again Mojang

Please fix this bug.In the screen shot below The world that I am looking at is the copy of my survival world which were both deleted when the game  froze in the world menu, In the second ss both worlds are missing and only backup worlds are present in which was a backup of the world 2 DAYS ago, I have lost almost 3 hours of work just from THIS bug