Hi, I don't know if anyone can help but we are...

Hi, I don't know if anyone can help but we are now onto our third formula with our 3month old son and he is still constipated. We first tried S26 Gold. He didn't experience any pain but his poo turned to nuggets so we changed him to Karicare Gold. We had him on prune juice which was softening his poos and making him go as soon as we stopped the prune juice he stopped going. He was then showing great signs of distress. Not sleeping, screaming, pasiing ALOT of wind and often grunting to do so and just being sooky - this is not my baby. We then changed him to Novalac Constipation. The lady at the chemist said she has never heard of any baby having a problem on it, I guess my baby is the exception. Today is day 3 of being on it and his poo is again turning hard. He won't drink boiled water, he won't drink apple juice and he will no longer drink prune juice. The midwife told me to add an extra 10-15mL of water to his bottle which I have done. We also have the normal Novalac to try as he can't stay on NOvalac Constipation. What do you suggest? We are going to take him to the dr but I was wondering whether you guys have any ideas? Thanx