Alamak, poop worry is real lah! At 1 month, babies usually poop quite a lot, color and consistency changes every few days which is totally normal, especially if breastfeeding vs formula makes a big difference. A few of us mums in the group noticed our babies' poop went from black (meconium) to greenish to yellowish within the first week, and that's perfectly okay. What matters more is if baby is feeding well, gaining weight, and seems comfortable, if you're noticing anything that worries you, best to check with your pediatrician just to put your mind at ease, especially since baby is still so tiny.