how can I give enough?

Selvidger

My lo was very jaundice for two weeks so I was trying to nurse with a shield and pump to supplement for weight gain. Finally was given a clean bill of health and could get back into nursing routine. It gas been VERY painful to nurse (pumping is ok) but I'm trying to stick to it. My lo just turned 4 weeks, Feedings are painful but I'm not in crying pain and am only pumping twice a day to give him a 4am bottle or to have something if we are out and about (not quite ready to nip). My question is: he will nurse for 30-45 mins, fall asleep, wake up and be ravenous. We often give a bottle because he falls asleep at the nipple and doesn't fully feed. I just gave him a 4oz bottle for this last feeding....I really don't think he can get that amount from me and I feel like nursing is so useless. How can I nurse and make sure that he's getting enough? I've left a couple messages with my LC but she hasn't called back.