Advice Please!

I breastfeed and pump exclusively but I have been dealing with a colicky/fussy baby lately with terrible gas pains so we tried nutramigen ( only 1-2 oz at night ) and then a bottle of Breastmilk or nursed and it really helps him a lot but now that I have that under control yesterday and today my baby hasn’t had a bowel movement yet just lots of gas. Do you think it could possibly be from the formula? What has helped your babies with colic/fussiness and has anyone else had any of these issues regarding bowels?