Breastfeeding

Hey ladies so I have a two months old and I don’t know why but whenever I try to breastfeed him which is once a day or once in two days because he makes the ugliest faces like it’s nasty..Some say that it’s acid reflux for which my pediatrician recommended zantac which I give him twice a day. But now even my breast pumped milk whenever I try to feed him it’s like he’s gonna throw up and I take the bottle from his mouth and try giving him again he closes his mouth so tightly. So my question is why does he cry so much and make faces when he hasn’t even touched my breast or the bottle milk if it’s from acid reflux why does he pulls away when he hasn’t even touched the milk?