Re: Why isn't she eating?
All babies kind of go through peaks and valleys in how much they eat. There were weeks where I wanted to tear my hair out at how little my baby was eating. But that seems like a long time... especially if it's causing weight loss. There are so many things it could be in addition to reflux. Some babies don't absorb nutrients properly. My friends baby had allergies that only showed up on a sigmoidoscopy because the irritation was confined to his bowels, and did not show up in any blood work or skin tests, and were unusual enough allergens that an elimination diet didn't do anything.
If I were you I would personally start tracking everything (time/amount of feedings, wet/poopy diapers, maybe weight if you have a reliable baby scale), and do that for maybe a week or two before calling back, so you have evidence, so to speak. But if it's really setting off your mom radar I would keep pursuing it.