change formula?

i recently started using the regular yellow enfamil i used to feed her breastmilk but my milk supply went DOWN so that's really not an option anymore, but ive noticed my 1 month old is really gassy, she's been pretty fussy lately i'll catch her like pushing and making faces in her sleep as if she's in discomfort? she has been pooping less like once or twice a day only when before she'd poop A LOT. i've been debating changing to the enfamil gentlease, any advice? is there any other formula that could also help? i'm tired of feeling like she's in pain and theres nothing i can do about it