I was working in a world and I had to leave my computer and it went to sleep. When I tried to get back in to the world, all I got was a white screen. When I rebooted my computer and went back into Minecraft, my main survival world I was working in was gone. I have tried various things and am unable to retrieve this world. I searched the problems and the closest one that I saw was MCPE1153 but I didn't see anything I could do on my own to fix the problem.