Minecraft entering bugged state

While exploring, randomly my character stopped its animations, even when running, jumping, sleeping, etc, even noticeable in the mini-character in the top left. The, I noticed it wasn't only that which was wierd. Llamas had their body vertically and when I leash them the leash aimed to the sky. Also, natural pufferfish seemed to get really long befor crashing the game. When I reload, it goes back to normal but after a while it gets buggy again, and starts to crash because of different things.