The good news is that your baby isn't lactose intolerant. Lactose intolerance in babies is extremely, extremely rare. A baby with lactose intolerance would not tolerate bm or any other milk from birth and would be very, very ill. Most likely there is another food sensitivity issue - perhaps coeliac - and the damage this is doing to the gut is causing secondary lactose intolerance. There is a very good article about lactose intolerance here - Australian Breastfeeding Association - Lactose intolerance and the breastfed baby. Coeliacs I know less about so I'm not sure if it could be diagnosed in a baby so young. I am wondering though if there was any connection between starting solids or one particular type of solids, and the problem starting.

Usually with food sensitivities (allergies and intolerances) a dietician who specialises in them or an allergist is the best place to start. Like any specialised area, a GP will only know all the ins and outs and latest info if he/she deals with it a lot or has a special interest in it. One general practice doctor just can't know everything.

Best of luck with it hun. It sounds very difficult for you atm.