Everything Gone

When I went in creative mode to build my world, I had a group of buildings in the End and in the regular world I built a huge village. Well, I built a Nether Portal and went in the Nether but didn't build anything, so when I go back to the regular world all of my things were gone. So I exited out of the game and went back in and it was still all gone. I am really disappointed because I spent many hours on that world.