Puppy won't stop eating her poop?

I have a 10 wk old long haired chihuahua and she is on purina puppy chow as she has been since she was weaned. But now within the last week she has started eating her poop. Its so gross please help me. Also I have bought her plenty of toys to chew on including puppy teethers but yet she still wants to bite and chew on us. Help with that too please