Why Am I Not Tired?

Can it be explained Scientifically, Psychologically or Theoretically?

Monday-Thursday
I slept an average of 5hr 30min a day

Fryday
I slept at 0530H and woke at 1000H on Fryday.
I worked till 8pm and left work at 2045H.
I went for a 5km/26min run, from 2137-2203H.
I had a Chicken Salad and Mango Smoothie.
I edited my essay, from 2230-0030H.

Saturday
I topped up petrol.
I pumped the tires.
I sent the car through a car wash.
I got home and finished showering at 0130H.

Now
It's almost 5am and I don't feel sleepy.
I can't get to sleep.