I would second and third and fourth the suggestions on completely avoiding milk and soy.
My son was exactly as you describe your baby and had been treated for reflux since only 2 weeks old. He screamed all the time, it was relentless, and feeds were a battle too. I got really severe PND, and I am sure that lots of it was from the stress of his condition as it wasn't my first baby either. So, so stressful. I really feel for you. It feels like you're in a different parenting universe from everyone else ...
Anyhoo, it turned out DS was completely intolerant to dairy (not soy in his case). He was on formula from 6 weeks (big problem, but unavoidable due to my PND) and he only improved really when on both lansoprazole (see below) and on a hydrolysed formula he would actually accept taste-wise (they are mostly vile).
If you noticed a difference when cutting out dairy, then I would say there is a very high probability she has a problem with it. You would need to do a dairy and soy free trial for at least two weeks to see if there was any effect - 3 days won't be enough. If it works, it will make a huge difference to your lives so has got to be worth a shot.
However, and it's a big however, if your DD is still having formula then cutting dairy out of your diet won't really make any difference. You'd need to either stop the formula or change it to a hydrolysate one - available on prescription from GP or hospital.
If it turns out to be the case that your DD is in fact allergic to dairy/ soy then it would be completely appropriate for your GP to refer you pronto to a dietician given your osteoperosis. Then you can be ultra-sure you're getting the right nutrients while on a restricted diet.
Regarding reflux meds... those doses of ranitidine sound on the low side, but I strongly stress I haven't looked up the info in the BNF for children. It is now quite commonplace to put children with confirmed reflux on a PPI drug like lansoprazole or omeprazole. DS was on lansoprazole which is far more effective for reflux than ranitidine, and easier to administer IMHO.
I stress I am not medically trained in the slightest but I am not at all sure what your doctor meant when s/he said that there was some kind of conflict between enfamil AR and the ranitidine. I am fairly sure that ranitidine wouldn't act to 're-thin' the milk... with carobel added into already thickened milk (as the doc recommended) I would be very surprised if any baby could suck the milk out of the bottle, unless you had enlarged the teat significantly or were using the fastest-flowing vari-flow teat on the market - it would be like wallpaper paste!
If she is following her percentile line then she does not need early weaning or introduction of more formula. She is absolutely getting enough. If she has a milk/ soy allergy, more regular formula could make things lots worse, not better (unless it's hypo formula).
Stay strong. It's awful, but there may be light at the end of the tunnel with a few changes here and there.