ALL MY STUFF DESPAWNED!!!

3 days after Christmas I went into my survival world, but I noticed that I didn't have anything on me except 29 levels. But my spawn was very FAR from my house. So I had to walk 300 blocks to my home and everything was where it was but each time I died I spawned very far away so I turned on creative and fix the spawn and got my stuff back, I didn't want to do it but I have to save hours of work. The next day I went into my world in which I fought the wither after I make a bunker and make spawn for it, I successfully did it and I haven't been in it FOR MONTHS, when I went in it I didn't have my inventory and EVERYTHING inside my chest and ender chest was NOT THERE!