Talk to Pediatric Nutritionist on Baby Feed

AoA, my child is 3.5 months old. He was 3.78 at the time of birth, but he gained only 0.02 grams in 40 days. After 55 days he was just 4.01 kg.

Doctor prescribed Meiji pre (to be given till he is 5 kg) along with breastfeeding to (before that we were giving lactogen 1 as my feed wasn't enough).

My feed still is not enough, we give meiji pre 4 ozs (ounces /points) twice or rarely thrice a day, as I want to give him more of my feed.

He is MashaAllah se 5 kg now. What should we replace meiji pre with? Plz suggest