Most Things Are Broken

For some reason I fall very slow. Any item like the furnace (including advanced items) no longer work. The bell worked when i first made the world, but now it just does the animation. The world chunks just randomly stop loading, so there will just be this huge hole that goes down until where bedrock is supposed to be. It only happens in a few places for me. Then it is just solid air that I can walk on. I took a photo of the unloaded chunks if you feel like looking at my problem.