It could be that he just realized that he can put up a fuss if he doesn't like something and get his way. I had a daughter who used to throw up every single night because she didn't want to go to bed, and that was with no nap during the day....and she was only a little over one year old.

Maybe it is from the seasonal changes. But think of the closer elements in her room. Is the heater noisy or does he miss the sound of the fan in his room from the summer? Are his clothes uncomfortable? Maybe it is the sun that it hitting (or not hitting) his room in the way he is accustomed to.

Then again, some children just grow out of naps early. He does still need naps, but not ones that are so long. Children can change suddenly like that...there is a reason, but we can't see it because, well it's biological. I'm sorry I don't have a better explanation. Also, check to see how much time he sleeps at night. If he is still getting the same at night or sleeping longer at night, then you will have to adjust the nap time accordingly.

He might also go in patterns too, where he will not take a nap one day and then crash for three hours the next. This is normal. You will see this same pattern when he eats. He might refuse to eat very much for a few days or even a week....and then hog it down for a few days to make up for lost time. It doesn't make sense to us because we are so time oriented, but it makes sense to them because they just follow how they happen to feel at the time.

Here is a chart that I like to give to all parents who are having difficulty with their children's sleep schedule. It isn't set in stone, but it's a good guideline. Good luck!

http://www.babycenter.com/0_how-much-sleep -does-your-child-need_7645.bc