my LO is 10 weeks and he can drink 3 1/2 oz. to 4oz. Of pumped breast milk in about 10 minutes and he does not spit up. When I breastfeed him, he will feed and spit up on my breast while feeding. Why would he spit up at the breast and not with the bottle? Any suggestions to prevent the spitting up while breastfeeding? It's such a night and day difference.