Hi Brandie,
I have a almost 5 month old son who had/has severe acid reflux. His doctor actually prescribed him the same Zantac medicine. He has been taking it since he was a little short of 2 months, and I will tell you that it actually works. He does the spit up thing less now, if at all most of the time. The only other thing, I can recommend is feeding him a smaller bottle, for instance, a 6 ounce bottle every 3-4 hours, which also helps with the acid reflux, it has worked for me, that along with the medicine.
The only problem I had with the medicine, is that, like adults, after taking it for so long, his system got immuned to it, so I stopped giving it to him for about a week or so, then started up again and it all worked out fine. Your Dr. should have told you to give the Zantac to him until he starts to eat solids. I just started introducing my son to solids ( baby food @ 4 months ) and he barely spits up now at all. So I would suggest for you to at least try the meds for a minute to see if it helps, and then if it doesnt try other things.
I will pray for your situation, i hated to see my son looking miserableand irritated from spitting up, so I totally understand your concern. Good luck!