I'm concern HELP PLS

I started working it's been almost 2 weeks. I was Breasfeeding my bby girl since she was born on demand . I will give her formula aswell when we wil go out. I will honestly hardly give her any formula . Now she just turn 4months today . So now that I'm working idk if it's the milk that she doesn't like but she's only eating 2oz every 2hours mayb 3 oz which is rare I try giving her my breast milk too n same only drinks 2 oz of a bottle  .. but funny thing is when I breastfeed her she could b on my boob for a while. Let's say I feed her 2oz n I give her my boob after she will still eat..  Idk what to do is it the milk is it the formula? She looks fine to me she poops  n pee good. Am I doing something wrong? I see my doc this Monday. For her 4months check up. Is anyone going they this? Or has happen ?