Cupcake's distress

So I haven't had to go in Cupcake's room at night since she started sleeping through the night on October 17th (I know because it was the night she turned exactly 3 months old).  Imagine my surprise when she started crying at 5 am.  My first thought was a growth spurt or she had flipped over.  She's still not able to roll from her back to her stomach but she's got the stomach to the back down TOO well.  She flips over a lot and wakes herself up.  It's annoying.  But she's never done it at night.

I sneak into her room, trying to make sure she doesn't see me.  There she is, crying with her eyes closed on her tummy.  I gave her some tylenol (she's been gnawing a lot) and moved her down in the bed so she wasn't in the corner.  As I moved her, her sleeve brushed against my hand.  It was wet.  Her sleeve was completely covering her hand....and her thumb.

Ahhh...the poor kid had been trying to suck her thumb through her sleeper, all to no avail and finally had to call me for help.  I rolled her sleeves up and snuck back out of her room.

I didn't hear from her again until 7:30 this morning, the little stinker.