31 weeks pp - breastfeed issue

I've very low milk supply since gave birth to my son, each pump for both breast added up only 1/2 oz and I gave up totally when my son was 3 weeks old, but luckily he had the colostrum from the early stage of bf. My question is, is it possible for our body to produce milk since it had stop for like more than 7 months? Coz I wish to let my baby drink bm for stronger immune system, currently he is on fm 4 to 4.5 oz every 4hrs. When I do hand express, my right breast still can come out with a very tiny little bit of milk.