I think macsmum is right about the Zantac and the dosing needing to increase as growth occurs. My LO is on Zantac and is also 7 wks. She takes 1/2 ml three times a day, but she has a pretty mild case of reflux. She is also very fussy in the evenings. I think when some babies are fussy or colicky, feedings help (as in my LO's case) and other times they seem to just aggrevate the fussiness further, which might be the case with your LO.