Animals laggy, can't go into first person in spectator mode

All the animals are really laggy and barely move. It's like lag in multiplayer, but this was on a single player world. I couldn't ride a horse, the slimes were seemingly frozen in midair. I tried to kill an Enderman but even though he was there on my screen half the time no hits would register, and even after 7-8 hits with a diamond sword he didn't die. The Killer Rabbit Of Caerbannog didn't attack me when I was in survival. I spawned it with an egg in creative, then went into survival, didn't work then, and then I tried /summon while in survival and that didn't get it to attack me either. I also wasn't able to right click to go into first person perspective of any mobs (not even the new ones) in spectator mode.