need help with milk supply

I need help i want to increase my milk supply.  i started birhcontrol at 6w pp im talking the mini pil . Before i started with birthcontrol  i was pumping 3-4 oz but know im only pumping 1oz i try mother milk and fungreek pil but it seen not working i just want to give up.. i pump 4 time doing the day for 20m .. i just dont know what im doing wrong