Still low milk at 2 weeks postpartum!

Hey there mommas. So I had my little dude 2 weeks ago and have been breastfeeding since birth. The poor guy had jaundice and has had doctors appointments pretty much every other day and has only gained a couple ounces since leaving the hospital. Doctor told me to supplement with formula to try and get his weight up. I’ve been having him feed on both breasts before offering a bottle. Even after breast feeding, he manages to finish almost 2 oz of formula. I can’t tell if he’s getting enough breast milk😩 I also try pumping and I barely cover the bottom of the bottle! 😭 Does it usually take this long for milk to come in or should I consult a lactation specialist? I’m getting super frustrated. Are there any sure fire ways to boost milk supply fast? My goal is to start stocking the freezer but at this point I’m feeling defeated 😔