Too thin

A trip to the local version of childcare learned us that our little Wriggly Bum is too thin. "She hasn't gained weight, so your milk production must be insufficient," says the doctor. He makes me feel like a horrible, insufficient mother. Surely I haven't gone through cracked nipples and painfully huge breasts in the last couple of weeks for nothing? Implying I'll have to start giving bottles and will never be able to nurse her, doesn't help either.
Luckily the nurse who explains what to do, gives a much more nuanced image. Feeding more often, and giving a bottle if she takes it, will probably do the trick. We've got some scales to check whether she'll gain weight in the next couple of days. If she doesn't, we'll make an appointment with our regular paediatrician.
Wriggly Bum is a happy kid, though. She doesn't complain about being hungry at all times, and when presented with it, she doesn't even take the bottle. She does eat enough, I guess. I just think she's got some difficulties getting started...