Breast Feeding And Bottled Milk With Cereals. Why Are The Baby's Stool Yellow?

Hi, My baby is 7 months old.Till 6 months i gave breast feeding sometimes bottle milk as my milk was not sufficient for him.Now i give him cereals at morning ,dal with ghee at afternoon ,fruits like carrot apple at evening and idly with milk at night,at midnight i give him breast feeding.His motion was usually yellow color semisolid but from the past 2 days his motion is very light yellow in color .He was sick one week before with 103 degree fever .We took him to the near by hospital and the doctor told to give calpol for 1 day with 5 hours gap,we did so and his fever came down to normal temperature ,they also advised to give calcimax 4ml twice at morning and at night,and iron 4 drops at afternoon.Is it because of that???