Hipp Organic Anti-reflux milk

Hi mummys, I really need some help and advice. My 6 week old baby is currently having 5oz every 4 hours of Hipp organic anti-reflux milk, but he seems to be suffering terribly with wind and is very unsettled unless over mine of my partners shoulder or in the sling. He is on this particular milk because he was vomiting quite bad on breast milk and aptimil and struggling to put on weight in the first few weeks, this formula stays down but he seems to have a poorly tummy very often. Please help!