Her weight is on the 50th percentile and her height is on the 75th percentile which is good growth and considered normal for her age. You did not state if she is vomiting at meals or not. When an infant stops or slows down in eating it is usually due to not feeling well. Here are a few suggestions to help with acid reflux. The feeding position is important and should be almost a sitting up position when feeding her. Burp her well. Never lay her down on her back right after eating or ½ hour to 1 hour after feeding because the acid from the stomach goes into the esophagus and causes pain. Raise the head of her crib to a 45-degree angle too so she are not flat on her back. Feeding her 5-6 times day does help. Feeding that way keeps the stomach acid constant which helps the reflux, she grows, and weight increases at a steady pace. Suggest returning to the MD to discuss changing medication and possible further testing if the changed medication does not show improvement. Thank you for your question.
If the medication has not improved her eating, then take her back to the pediatrician. If you don't feel like her doctor is taking it seriously, get another opinion. Your baby needs the nourishment, and if her doctor can't help you, ask to be referred to a specialist that would deal with these issues.