My slow gainer

I’ll try to keep this brief, but I’d love some feedback.

I’ve been breastfeeding and supplementing with formula since day one (I have a low supply due to a breast reduction). For the first 9 weeks of her life, she was gassy, fussy, arching, unhappy, and not gaining quickly. I switched her to soy formula and cut dairy out of my diet, and that made a big difference in her general happiness level. She also gained 6 oz in a week, which was the most she’d ever gained. But the next week she gained nothing again.

I finally suspected reflux (I thought spitting up was normal, and didn’t realize normal spit up is just a little) and talked to the doctor. I think she suspected I just wasn’t feeding the baby enough, so she told me to stuff the baby with as much formula as possible, then we’d do another weight check. She gained 11 oz that week! We still put her on Zantac, though, because she was still spitting up a ton. The next week she only gained 4 oz. (I’ve been feeding her 26-30 oz of soy formula, plus breastmilk.)

We tried Similac Alimentum and she hated it and turned her face away. Then she threw up everything she ate and stunk like buttermilk. She ate far less the day I tried it than usual, so I called that one a failed experiment.

I thought her spitting up had gotten a little better on the Zantac, but in the last few days it’s been like the Exorcist around here again. After one feeding last night, the cloth diaper I had been using as a burp cloth was totally soaked and needed to be laundered.

I’m checking her weight again tomorrow, but I don’t feel good about it. She’s over three months old and just broke ten pounds last week.

I read some of the forum, and I think I might request that she see a pediatric gastroenterologist and try a PPI. Any other thoughts or suggestions for me? Thanks in advance…