No icons on the screen while playing

I went on to the Minecraft pocket edition and loaded one of my worlds and I expected for there to be and chat icon, menu icon, and the touch pad. Instead there was nothing on the screen except the view of my world. I can still press the buttons if I can find them. It like they are still there, only invisible. It's the same way on all of my other worlds wether they are creative or survival. Which is why I labeled the game mode as none. I have tried closing out of the game too no avail and I haven't found anything in the settings that would change it. I can't even play the game because I don't have my hot bar and I can't find/go into my inventory to select an block. I can still place and delete blocks (only it is stuck on the last block I used) and look around. Like I said, I can't still use the buttons if I can find them. It is the same on all of my worlds and the only thing I haven't tried is deleting the game but I'm afraid to do that.