Failure to thrive @ 4 weeks old EBF

Gabriela

My baby is now 4 weeks old and barely back up to her birth weight. We had a hard time matching because of lip and tongue tie but have since gotten that resolved. Shes having about 4-5 poopy diapers and 5-6 wet diapers a day. Nursing often. I don’t understand what I’m doing wrong and why she’s not gaining weight. My pediatrician is worried about failure to thrive. I’m getting bloodwork done on her now. Any similar experiences?