whn my lo was a newborn and i expressed, he would only have 2 or 3oz at a time. i deffo think that your lo will let you know when he has drank enough. deffo speak to ur hv though if u are worried but im sure its nothing serious.... newborns and babies are like us, some days we are really hungry, other days not so much! how many hours does he go between feeds?? and how much has he dropped by? remember his belly will still only be teeny weeny.