Preemie weight gain

Ana • Truly blessed 💗
I delivered my twins early at 34 weeks on 4/15. My girl weighed 2 lbs 11oz at birth. She is now their 3 months and she weighs 8 lbs 6 oz. and she also had reflux. our pediatrician referred us to a grastroenterologist to see why her weight and growth have slowed down. She eats every 3 hrs and its around it ranges from 2 1/2 oz to 4 oz of either 24 cal neosure or fortified breastmilk. Anyone else having similar issue?