Constipated LO

Mixed feeding po si baby, he is 7 weeks na po, and nagchange po kami ng formula milk, from similac to s26 pink, but the problem lalo di nadumi si baby sa s26, unless I suppositories ko sya, but today kahit nasuppository ko n sya, hindi pa din sya po pumupo... Ano po magandang gawin??? #pleasehelp #firstbaby #1stimemom #advicepls