Sleep!*?!*

Can someone please explain how it is possible to go from waking up 3 times a night with taking only 2 little naps throughout the day to sleeping 9 straight hours with having 5 little naps during the day? This whole growth spurt thing is killing me. We had established a pretty decent schedule throughtout the day, but the last few days have been nuts and nowhere close. You;d think after 4 months I would have some understanding of my own child, but I'm just as clueless as the day we brought him home. At least he is finally giving up this whole crying business, or at least it only lasts about 45 minutes instead of 2-3 hours.