Jennifer
Have you considered a food allergy? My 18 month old also has food allergies and as soon as discovered it was dairy and eggs and eliminated those from his diet he has been exceptionally well, sleeping throught the night EVERY night, and just a more agreeable child! And I discovered all this no thanks to my pediatrician - I've also discovered you have to educate yourself for the most part and become your childs health advocate b/c nobody else will.. Email me and I'll tell you more!