Advice please

Ok so I have a 3 week old baby who was born at 41 weeks. She has always been a content baby but when it comes to food she can definitely eat. But she will eat what seems to be too much. She will drink a 4oz bottle and still cry and act hungry for another. I think 6-8oz is too much for such a young baby. Any reason why she is doing this? I breastfeed her during the day and she gets maybe one bottle of formula throughout the night but even with breastfeeding she never seems full even though I know I’m making enough milk because I can pump 20oz each time