You asked Google: "Why didn't I just sleep?" And Google said:
A) You didn't sleep because you were too busy binge-watching cat videos.
B) You didn't sleep because your cat took a liking to your pillow and would not let you have it back.
C) You didn't sleep because you ate too much pizza. It was a long night.
D) You didn't sleep because you were too busy contemplating the meaning of life and the futility of existence.
If you're still awake, go ahead and take a look at our Ramblings of an Insomniac.