After update all worlds are extremely laggy and pixelated.

Game crashed and automatically updated. Device lagged and did not show that the game had been updated. Tried to join the world that I was working on. Glitches into game everything was extremely laggy. Graphics were completely messed up- pixelated and laggy. Joined a different world to see if it was just the one. Same thing happened with that one. Refreshed Minecraft. No change. Logged out and in again. Didn't work. I would appreciate some help. Thanks.