exhaustion

Right before the donkey gets used to not eating anymore, he dies. And right before I get used to sleeping very little, my strength gives in. I've been sleeping between 3 and 7 hours (on average 5) over the past couple of nights, working until pretty late on my various intellectual tasks. This semester is very stimulating, and I was lucky to have a motivating presentation partner from whom I learned a lot. That's also a curse though, as it makes one want to outdo one's self.
In any case, I seemed to be doing absolutely fine not sleeping very much. I would go to work and go to uni and go about my business and feel absolutely fine. This afternoon though, I suddenly felt how every ounce of energy in my body was leaking - my knees started to hurt, and this special kind of tiredness one gets from lack of sleep - not sleepiness, but rather a general physical exhaustion, the absence of strength - crept in.
But that's not the end of it. Tomorrow, I'm giving the presentation I've been working on all those nights, and then I can start working hard on the presentation I'm giving the following week.
I've hardly ever been so motivated and focused throughout my studies. I'm enjoying it.