My b/f baby was not gaining weight properly (and started losing at one point) bacause he kept bringing up a lot of his feeds. We have been prescribed IG which is great - very little posetting and good weight gain. However, the IG affects his poo and ds has now not pooed for 3 days. Last time he went he seemed to stuggle and went bright red whilst pushing. Any advice on how to deal with a constipated b/f baby?