So my doctor told me at my 6 week that the pump has nothing to do with how much i actually have I’m…

So my doctor told me at my 6 week that the pump has nothing to do with how much i actually have I’m my breasts and how much baby is getting.i get 2-3 ounces per pumping session. My son sometimes does seem like he wants more but is having wet diapers and pooping . He gets one formula bottle a day at night when I pump. I’m just worried he’s not heating what he needs from me