8 month old constipation

I need some feed back anyone dealing with constipation?? I breastfeed and substitute with hipp organics. she spends half her time with one grandma and half with  the other. I work full time. Not sure what she eats, is it the formula. All I know is I get back at the end of the day is constipated, unhappy baby. I've used glycerine suppositories that work, she goes poo but it's so hard, it's breaking my heart. Any help???