Bedtime, waking up, why am I still awake?

So I finished what I absolutely had to get done for tomorrow. Which was not including my rough draft for my essay that was really quite important.

But I decided it was time to go to sleep. So I got all ready for bed:

Then I was lying in bed thinking about my essay, when this happened:

And I just felt like I could write some more of my paper. I don't know why. I am not happy about it. But I got out of bed and worked for another half hour or so on my paper. 

Now I am getting less than 6 hours of sleep tonight and I am going to be like this in Spanish tomorrow:

Somehow I am not tired though. Why am I still awake?