A.M.
You already have many good responses. My additional suggestion (if you have not tried this):
Though reflux is her problem, it may still be better if you carry her in an upright position after she eats, as well as when she appears to be in pain. The upright position may assist in her digestion and decrease reflux; the actual problem may not necessarily be what she is drinking (although it can become so from continued reflux) Carrying her will also provide much needed comfort when she is in pain.