To increase mothers milk supply. Supply?

Hi, Am a mother of 4 month baby boy. Initially i faced milk supply issue and my son was never use to latch untill he was 1 month old. So doc suggested me to govd him formula after everry atempt to breast feed. So i used to give an attempt then used to pump the milk and last i used to give formula as addition since he was hungry In second month he learned latching so i used to feed him directly instead pumping and then formula feed as my supply never raised. More than 50 ml per day. Now from.past a week i feel again my milk supply is lesser than earlier. Not feeling any leakage or heavyness. Have tried lactare and perinom tablets and lacting powders aswell no good results. Hence pls suggest some alternatives as i would like to feed till 6 monthx atleast. Is it 1st month non latching from.my son is the reason for insufficient milk supply ? PLEASE REPLY.