Doc tells quality of breastmilk is bad.

My baby is 7 months 20 days as of today and is on solids I'm feeding him home made uggu ( mixture of rice and lentils ) so before starting solids also he use to spit up milk and just to be clear he is completely on breastfeed and no formula.. we went for regular checkup to ask about spit ups and he told it's GERD and has suggested lanzol and aristozyme.. also he told my baby has calcium deficiency and I questioned him how come you can tell with just physical examination he is like by looking at head structure but just to be clear my baby was very soft when he was born last month April 15 his weight was 6.78 and as of today 14 may it is 7.68 .. he is rolling moving forward sits when given support he is super active baby . But the doctor tells me my milk is just having water you have quantity but no quality ... he says my milk is not having calcium hence baby does not have calcium .. can Someone suggest me what to do what test to take for baby and me also does breastmilk have no quality