supply questions

I had my son via csection on Nov 6th. He weighed 8 lbs 9 oz. Before leaving the hospital he weighed 7 lbs 12 oz. At his 2 week check up, he only weighed 8 lbs. The pediatrician told me to start supplementing with formula following breastfeeding. I finally got in to see a Lac Consultant this week (3rd week following delivery). She weighed baby, had me bf on one side, weighed him again. He had taken in 1 oz. Then we did the same for the other side. He'd only taken in 1/2 an oz. She said he was latched but seemed to be a lazy eater. She suggested I pump following each feeding if I wanted to keep breastfeeding. I opted to switch to formula because I have 2 other children at home and thought this would be very time consuming. THe lac consultant did suggest a few reasons why I might not have had my milk "come in" following delivery: anemia or pieces of placenta left inside following my csection. How can I find out if either of those scenarios is true? I'm not trying to go back to Breastfeeding, just want to know if something prevented me for getting my milk and if there's anything I need to do now to be healthy. Thanks Update: Talked to the nurse/midwife at my Ob's office. SHe ordered bloodwork for thyroid and anemia problems. SHe also prescribed Reglan to help boost my supply. ANyone know anything about this drug?