Hi. When can Postpartum depression occurs? Can that happen after 8 months of delivery? Can that happen anytime?

Hi everyone..am 20 week pregnant am getting utrus pain is ths common? Or wt plz tell me wt to do

My baby is almost 1 month old. From the time of birth ( c sec) my bm is not sufficient for him. So we are giving buffalo milk suggested by doc. But, he needs more quantity milk for 2 nd month but my bm is not sufficient for him. And my bm is not coming with force. Suggest me how to increase bm and how much time babies general drink bm ?