Birdie gained back the weight she lost. And then some. So, YAY.
I'm not going to go all into what we did to get her there right now because honestly, I'm a little tired of talking about it, hearing opinions, listening to suggestions, etc. No one has done anything wrong, I'm just a little burned out.
The ped did say that failure to thrive is fairly rare in breastfed babies Birdie's age. This didn't make me feel better or worse. We're still watching her and she still has to go for weight checks, but the situation is much less alarming/dire/panic-inducing.