Constipated from formula

So my newborn is strictly a booby baby and is now a month old. His pediatrician says to give him formula during the day and breast at night, she's says the formula will help lower his bilirubin levels. So we got similac sensitive and he's been constipated! He's so gassy and fussy now and we only used it a day and a half. He usually has about 4 poopy diapers a day and has not had one in the last 24 hrs. Does formula usually make babies constipated and gassy?