Minecraft is taking really long to load and all my worlds are corrupted

Hi i'm reporting (in my opinion) a pretty major bug. One day i booted up minecraft as usual and the world me and a couple friends play on is corrupted. After this the game now takes an abnormally long time to load and any world I try to play eventually becomes corrupted. I started playing on a friends world so I couldn't corrupt it. But today I played it and ALL my worlds are gone and it says I need to enable multiplayer settings/realms to play with friends and on servers even though I can play other multiplayer games just fine and I could play friends before. Please look into this it is making the game just about unplayable. Thanks in advance