Good evening, moms, I have such a question))) how do you understand th…

Good evening, moms, I have such a question))) how do you understand that the child wants to eat? (more precisely, feed on demand). My daughter cries and searches for a breast every hour (as I see it), so my breasts don't get enough to feed her. She wants to be next to me and play with the breast. She sucks, then she throws up, then she bites... In the morning especially. And when I put her down, the milk flow is very low, and the baby starts to fuss, wants to be fed... Also, in a week we will be 5 months old, does the baby not eat enough or something, I spend a long time putting her down + the stomach hurts...