Timbang ni baby

Hi mga Ma! Ask ko lang po kase nung 2months po Lo ko timbang niya is 4.5kg, 3months po niya is 5.5kg then 4months is 6.5 but now he is 5months but his weight is 7.1kg is it normal or what feeling ko ambaba ng nadagdag .Pure Breastfeeding po ako #pleasehelp