Soo now when I leave my son with my mom he won't eat formula at all and will wait for me to come…

Soo now when I leave my son with my mom he won't eat formula at all and will wait for me to come back home to breastfeed but I don't pump enough so I don't get enough for bottles should I take something to increase my supply so I can pump? I have a ton in my breasts at times but never pump and when I try I don't get much in the bottles and my baby eats quite a bit?