Breastfeeding/ pumping

So My son is 5w and never really latched due to being in the nicu and my supply came in late and now I feel like it’s drying out. I was Im a long labor the lasted about 3 days until I got a c section. And I didn’t get any bonding time right after birth due to him have some breathing problems and had been rushed out of the room. I get preeclampsia and high blood pressure so I couldn’t see him till over 30 hours after birth. Now that I try to pump little to none come out. I’ve tried teas and supplements to help my supply but nothing seems to help.