Why can't I sleep

It has been countless nights that I wake up early in the morning because I hear Kaitlyn cry. I go into her room and put her blanket on her, and return to bed. This is where my problem comes. I cannot get back to sleep. I think about all the things that need to be done at work, at home, everywhere. What I really should do it get up and go do something around the house, but the bed always feels to good. So, I just lay there trying to convenience myself that by just laying there will give me enough energy to get me through the day. After about t30-40 minutes of laying there, I finally fall asleep, only to be woke up by the alarm 15 minutes later. I go through the day trying to stay awake, so the little buggers at work do not kill each other. When I get home, Rob and I do the normal parenting things at night- homework with Logan, playing with Katie, and on the special nights bath time. Then we take the next 45 minutes to put to bed Logan and Kaitlyn. Finally, the kids are in bed, and all is quiet. I think to myself how tired I am, but find myself glues to either the t.v or facebook. Why don't I just go to bed????? Here I am at 9:30 typing on my blog wishing I could go to bed. What is stopping me? Why don't I just walk up stairs and lay in the bed that feel oh so good in the morning. I really cannot answer those questions, for if I could, then I would not be here right now.