Look, because of what I do, I end up staying awake a long time during the night - thinking about conferences and whatnot. I must say that actually staying awake from 10:30 to 4:00 AM does not seem like a blink of an eye. It seems more like an eternity, as sleep never comes. What you are probably experiencing is deep thought, where your mind doesn't slow down and you actually skip the dream-state of mind. When you are in deep thought, you can fall asleep, wake up, and not even realize that you fell asleep - you might not even be tired. This has happened to me about three times when I was younger.
If you don't get extremely tired during the day, then you are actually getting a good bit of sleep, however, because of this deep thought, you might have a large amount of mental stress. I strongly recommend that you take a sleep aid so you can relieve any mental strain you might be experiencing.
Happiness is not about being perfect.
It is about seeing beyond the imperfections.