My son is 9 weeks old he smiles and interacts with me throughout the day but at night he's a whole other baby. starting at about 11pm he will fuss and scream from 3-5 hours. he will fall asleep for about 30 minutes maybe two times during that time but that's it. it takes me so long to get him comfortable and to sleep for longer than 30 minutes. he is on Similac Total Comfort & has been for about 3 weeks now. also, we've tried gripe water & it babrely helps.