Infinite Death Loop+Entities Vanishing

At night, a creeper exploded practically on top of me, and I died. On clicking respawn, there was an enormous amount of lag as well as the Windows 8 "thinking circle" indicating that something was taking up an enormous amount of resources. After about twenty seconds, I was suddenly allowed to move. I attempted to sleep in the bed to get rid of the night cycle, but the game acted as if I hadn't even right-clicked it. I went outside and realized that either every mob had vanished, or every mob had become invisible and soundless.

I then attempted to retrieve my stuff, which was also apparently invisible. I stepped into the crater, and then the game killed me for no apparent reason, bringing me to the death menu. So I clicked respawn, and went through the entire above process again, just to confirm that I would die again. I only died when standing in approximately the spot where I had first died.

On third respawn, it thought so hard that I was kicked from the server, even though I was in single player. It brought me to the multiplayer screen. I attempted to enter the world again, but it started me off where I had died. I could see all of my items and zombies in the distance, as if it had been just after the creeper explosion. I clicked respawn again, and then after going through the lag, I went into spectator mode. However, despite that, I was unable to move through any blocks. I then went back into survival and quit, thinking that perhaps if I relogged, all the mobs and my items would reappear. Relogging brought me back to just after the creeper explosion again.