Redirected to title screen after login attempt to single player world.

When attempting to log into a single player world, the game remains at the loading screen for approximately 30 seconds. Immediately after that amount of time, the game redirects me to the menu screen. Going back in, I noticed that a new world was created automatically, without me doing anything at all. It is unknown what could have caused this other than the possibility of playing for too long in one go. I was playing for several hours non-stop before this happened.