In need of encouragement

I'm becoming very discouraged with breastfeeding. My entire pregnancy I looked forward to being able to nurse my baby and have that wonderful bonding experience. But ever since I needed to have a c-section I feel like my body is failing at the one thing it's made to do. My milk didn't come in until day five pp and I wasn't even sure it was in because my breasts didn't engorge nor did I leak at all. LO has lost so much weight (1 lb. 6 oz. as of Friday) because of my low supply and I don't even want to find out how much more come Monday for his weight check. I've met with a lactation consultant and she made me feel very confident that I could get my supply up. However, as I noticed how little I pumped (not even a quarter from both breasts) and how little wet diapers he is making that confidence has turned into worry and tears. My boyfriend keeps pressuring me to give him formula but I know if I do my milk will surely diminish, but at this point I see no other option. I think I'm starving my little boy.