@Gelati: I don't know why all the sudden that DS had the reaction with Nan comfort. He was doing ok with it other than the severe gas issue. Initially, we thought it might be a bad tin so we opened up a new tin. The frequent pooping episode didn't go away. I don't suggest you to switch formula. Perhaps just rice water and breastmilk for a while for now? Unfortunately, i don't have an alternative other than the formula. DS now has severe nappy rash. It hurts him when i wipe his butt and put the cream on.
That's my feeling too. If it is gastro, it should be cleared by now. At least your GP is willing to do something. Our GP just told us to wait and see last time after 1.5w of pooping!
We will get another tin of lactose free tomorrow just to clear his diarrhea. Then, we have a paed appt on Wed.