I can't sleep

I am averaging about 2 - 3 hours a night and I am starting to get cranky. I can fall asleep no problem, I just can't stay asleep. At around 4 am every morning, I wake up and there is no more sleep to be had. Desoto, of course, thinks that because I am awake it is time to go for a walk, so he stands beside the bed and alternates between excited panting and whining. You would think that I would just give in and get out of bed, since I know I will not be sleeping any more, but no, I refuse to give up hope and I lie there, tossing and turning, getting more and more pissed off that I cannot go back to sleep. Getting up would mean that the no sleep wins, even though it does. This also means that I am late for work every morning because I will try to sleep until the very last possible second, even though I know it is pointless. I am sure there is a life lesson here that I just refuse to learn.