Worlds Getting Deleted

2 months ago I was playing in my Survival World. When I went on the xbox app, the application locked up to where my screen froze, and then it crashed my computer. When my computer reset and I went back on Minecraft, my world got deleted. I couldn't find it anywhere in my World list. Today I lost one of my Server spawns that I recently updated. The same thing happened again where it deleted my world and it was before I could make a copy of it, and I lost the entire map. Thank you for listening, and I hope this will help.