Game mode changes mid-game

Put the summary of the bug you're having here

What I expected to happen was...:
I expected to play survival mode as it should be. I tried going out of the world and going back in. It shows as survival mode still but when you log back in, it is in creative mode.

What actually happened was...:
I am playing Survival mode casually for 2weeks now. With the same world. Suddenly, I noticed that my hunger and life bar have disappeard. I did have no idea what have happened and when I opened the inventory it shows the choices of items for a creative mode which is not what I expected. I still have my item and it was mid-game when this happened.

Steps to Reproduce:
1. This is unnecessary as it was not initiated and might have been triggered deeper.