Split Personality?

I can't figure out this little person! *laugh* On Tuesday, nothing could make Ashlynn happy and she spent most of her day yelling at the top of her lungs. Yesterday, she seriusly spent ALL day sleeping (even falling asleep in the middle of eating) and I took her temp cuz I started to worry she might be sick. She was fine. Today, she's happy as long as I'm dancing around with her to Christmas music. If I stop, I get an earful. Though food, of course, works to keep her quiet too. How come the trick that worked one day, doesn't always work the next???