Oh man, raising an infant and sleep deprivation hit me too. For about a week, I had to just chart if I was awake or not and just sleep when the chart said to sleep...
Other than the couple of times where I ended up not sleeping for 24 hours, I thought the wake up/eat/sleep cycles around 2 hours were ok, but 3 hours was torture, the wakeup would always happen in the middle of deep sleep and really mess things up. Once it got over four hours, it all seemed fineish. Not a lot of memory retention from that period though. Pretty happy we had a good sleeper or I would have been wrecked.
Other than the couple of times where I ended up not sleeping for 24 hours, I thought the wake up/eat/sleep cycles around 2 hours were ok, but 3 hours was torture, the wakeup would always happen in the middle of deep sleep and really mess things up. Once it got over four hours, it all seemed fineish. Not a lot of memory retention from that period though. Pretty happy we had a good sleeper or I would have been wrecked.