Thanks RCW. The staying awake through feedings was definitely our initial problem. She'd latch on and suck for only a couple of minutes before falling asleep. That's when I started pumping because not only was she not eating, but she also wasn't stimulating my milk production.
We did do a pre/post nursing weigh-in with the nurse a few days ago and she got 25 mL off only one breast, which is very good (our target is 40-50mL per feeding, assuming 8-10 feedings per day). And my breasts are definitely full now.
I'm just wondering where all that milk is going, if she's not putting on weight?