My daughter is 3 months and 10 days old. I breast feed my baby but sometime I used to feed her cows milk( as suggested by doctor) as she was not gaining enough weight after breast feed and used to cry a lot and gradually she gained weight to 4.5 kg. But from last 15-20 days I am breast feeding her and reduced feeding of cow milk to minimum. And as a result she has lost weight and now her weight is 3.18 kg. What should I do. Should I give her formulae milk? If yes then which can I give