6 week old baby with reflux and constant poo?

Hi, my six week old son has a form of reflux where we can not have him lying down flat as he tends to regurgitate alot. We had him on 'Nan AR formula' and he was pooing so much and the flatulance and poo was very smelly so we change him to Karicare De-Lact and his poo seems to be changing in apearance and smell but because it is thin he is still bringing it up. Can someone please suggest anything apart from SEE A DOCTOR. thanks :)