baby breast feeding wear for bridesmaid

Hi I have a question for all the other moms! Im a first time mommy, my son will be a month old in a few days, and his eating patterns seem strange, sometimes he'll eat 4 ounces and be full, and then sometimes he'll scream and cry until he gets 6 ounces, nothing else will soothe him, he spits his passy out and rocking doesn't help. Then other times he'll only take 2 ounces and he'll go straight to sleep. His pediatrician didn't seemed worried about him taking the 6 ounces, he's gaining weight and growing perfect so far, but everyone I've talked to says that a baby his age should only be taking 4 ounces every 4 hours. I don't want to not feed my baby when he's hungry but I also don't want to over feed and him have tummy aches! Has any other mommas had this happen? Is it normal? Thank you all in advance and God bless! baby breast feeding wear for bridesmaid ??