She took in 4 ounces when she nursed which is awesome!! I would just up feelings. Get lo to nurse every hour and half to 2 hours instead of waiting for her to cry (if that's what you're doing now). Just offer breast breast breast and see what happens at her weight check. And def check with a lactation consultant before supplementing. Maybe call your ob office/clinic to see if they have one on staff. My hospital has one and they were available and happy to help just over the phone with my questions.
Abby-mama to two beautiful boys (12/09 and 3/12), and wife to my fabulous DH