Mabagal ang pagdagdag ng weight ni baby

Hello mommies! Praning mom here. Please help :( Baby ko was born premature at 1.9kg only at 33 weeks. She is now 8 months old but ang bagal ng weight gain nya. Ung height and neuro developments nya like paggapang pagjump etc are all okay except for the weight. Sobrang takaw naman nya pero di ko alam bakit ang bagal :( She is eating solids nadin but in 1 month .3kg lang nadagdag sakanya. Any tips what to do? Her pedia told me na to check with gastro and endo. I'm just really worried as of the moment pero wala naman syang sakit. :(