I will try my best to explain this in as much detail as possible.

I logged back into my single player world and keep falling into the void, on earth.
I had 'solar fray' affect.
I turned LAN on and enabled cheats so i could go into creative. i then made a rocket and went back to the moon, it took me a minute but i found my base.
I had no grave, (i could find at least).

I have screen shots as well, i don't know what caused this, my only guess would be i closed the game while it was not responding.

Hm, weird. You get teleported to the moon if you switch the world to the overworld so it seems that nothing teleported you.

Did it happen only once?

This got me kind of unmotivated to continue playing once i lost all my things, if you want i can give you the world save or try re-create it. (i really don't want to try and re-create it but i will).

Thats a yes, only once.

I will close this for now as there is not really a way to reproduce it and as it happened only once and not frequently it shouldn't be a big issue.