Hi,my Baby Is 7months Old..till Now She's On Isomil Formula

Hi,my baby is 7months old..till now she's on isomil formula feed as she has got lactose intolerance last month we wanted to shift to nan pro and gave one feed of it she developed vomitings then we stopped that feed..and continued giving isomil .my baby is only 5.6 kgs on weight but shez active..is there any substitute for weight gain? Can we continue giving isomil?we even started cereal food but she's has same vomitings.nestle products are reacting my baby though she is accepting cereal foods.what brand will u suggest me in substitute of nestle?please kindly help me for my regarding questions thank you