i was working on my Minecraft world when it suddenly got really low fps - 0 fps 

i was not using anything that should increase lossage of fps. my game suddenly crashed and I was forced to shut down my computer. I switched it on and opened up Minecraft and selected single player worlds. I was expected my Titanic world to be on top of the list which appears. It wasn't. I checked everywhere on the list. It wasn't there. I can only believe that the world has been deleted. I had spent hundreds of hours on that world working on that build. It was a build of the RMS TItanic. That was the reason that I actually joined the game and went on the game for quite a long time. I cannot describe how much sorrow I feel at losing this build. If you could please help I was on version 20w14a snapshot. I do not know if there will be a way to get this build back. If you could thank you. I am only 11 years and old and I do not know how to work the files very well. Thank you.