my baby s now 3 month 2days old..last month on 11/7/2021 he was weighing about 5.5kg and on 28/7/2021 he weighed about 6 kg.....is it normal weight ? I feeling reduced breast milk for me.. any milk formula can I use?

A. weight of your child should be increasing by approximately two eyes the birth weight by the age of six month and 3 X the age of one year all you need is to ensure that your baby is otherwise active and passing urine