Hi My baby boy is 48 days old his birth weight was 2.9kg nd now he weigh 3.5 kg He is on exclusive breastfeeding only Is it normal?

A. 600 g is little less right now it should be more than 750 g because I would like to tell you how we calculate the weight as per medical base is 500 g minimum gain every month so that’s not happening so I would advise you to start giving formula along with your breastfeeding