Ds is 15wk for the past week or so he's not been enjoying a bottle at all he's crying and going rigid only a few mouthfuls in. He's never been a windy or sicky baby til now he takes ages to get any wind up I can tell it's hurting him. It's taking an hour just to get half a bottle down him. He's sleeping fine and isn't crying when he's awake it's only when he's feeding does he seem to be agitated. Any suggestions?