I've done hours of work, and the auto save was on. And kept saving but when I got off for a few Nd got back on all my hard work was gone.

I've done hours of work, and the auto save was on. And kept saving but when I got off for a few and got back on all my hard work was gone. My world isn't syncing and its making me mad. I've had to restart this twice already. 

Also idk what version it is.