Riley would be extra fussy whenever I ate large amounts of dairy. I say "extra fussy" because he was just a high needs child in general, but this was more than typical for him. He also had excema, sniffly nose, red ring around the anus most of the time. By doing the elimination diet, that is cut out all dairy from your diet for a minimum of two weeks, including trace dairy found in bread etc, I did see that his skin cleared up and his bum got better and he was less fussy. But it wasn't as dramatic a change in temperament as I would have liked to have seen

I slowly started to reintroduce dairy gradually and found he was okay if I ate trace dairy in bread etc., but having milk on cereal would cause a reaction. When I intro'd cow's milk at a year, I found he could not tolerate it at all, so now he is on Rice Milk. He does fine with yoghurt.
If she is gassy, another thing you could try is block feeding, where you nurse from one side a few times in a row. This helped us a bit. I don't have experience with the reflux meds, but I have read on here that sometimes it can take a while to take effect, or sometimes you may need a different med.