Hello My Baby Will Be 5 Months Old After 8

Hello my baby will be 5 months old after 8 days.At start for 2 months she took only breast milk sometime liptomil AC due to colic then completely on liptomil AC ,when she is 3 month she fed on liptomil (general) then due to hardly available in every pharmacy the pharmacist suggested novalac 1she is being on novalac 1 for 1 month the problem is that she is not gaining much weight now than she was gaining before should I change her formula to any famous brand like similar or nan ? One thing to notice that my baby is not taking my milk since 2 months and lactogen is not available where I live.Waiting for your suggestions