Distracted.

Elizabeth, who never has any problem going to sleep at nap time (she is usually asleep within 4 minutes of her head hitting the pillow), was tossing and turning today. I left the room with her awake, which has never happened. About 20 minutes later, I hear some breathing at the door so I open it up and there is Elizabeth. She says, "I need to go poop!" So she goes to the toilet, poops and then goes back into the bed and falls asleep immediately.