It's interesting that you lost your ability to focus after 5 days of sleep deprivation. I've been to meditation retreats where I'd get about 5 hours a night to lie down (not necessarily sleep), the rest of the day, no lying down was allowed. The ability of the participants to focus and concentrate usually became better as the days went on (that's the whole idea). Of course, that's getting nearly twice as many hours of rest time as your schedule. But then again, the rest was meant for the body, as long as one wasn't asleep, one was supposed to be practising.
