First post....my son is 7 weeks old. I changed him to aptimil comfort milk from aptimil first milk about 10 days ago. Since then he has strained terribly everyday for a poo and is clearly in pain with it. He is pumping all the time and they smell awful and again are clearly causing him pain. He is screaming sometimes for hours on end and when we feel his tummy it seems to be bubbling and having what feel like little spasms. I'm wondering if anyone has changed back to the original milk from a comfort or if it will cause more problems? Thanks in advance x