explanation required

My sweet daughter woke up at 3:15 this morning.

I was up with her until 5:45, when I succumbed the heady combination of sleep deprivation/sinus infection and sent her in to her father and passed out in her bed.

Marc and Stu left for work/school at 7:30 and Marc put the tv on for her. No I am not proud, but hello, I figured it was one of the only ways we were going to survive today. I crawled back into my own sweet bed and passed back out until 9:15.

She is bright and chipper and talking a mile a minute. She has been up since 3:15. I on the other hand who was only awake for 2 1/2 hours of that time feel like I've been hit by a truck.

How exactly does this work?