I credit Zantac, taken usually at 1/2 dose at night for eight years as the straw that broke this camel's back. I'm sure that was more than enough to completely change my stomach flora. Around that time an infection on my foot made antibiotics necessary and, bam, within 6 months I has sores in my mouth (to which my doc said, "Gee, only people with AIDS have sores on their tongue like this...").
I had a very hard time getting off the Zantac, but what finally worked--call me crazy--was beginning to chant with some local Buddhists. Maybe it relaxed my gut, or possibly stimulated it; it certainly made me feel better emotionally. Over the years, about a decade, actually, I worked on my gut with probiotics (which i didn't tolerate at all at first), then adding raw foods (ditto), adding a tablespoon of fresh-squeezed lemon juice to a bit of water and sipping with my meals (I haven't been able to tolerate Betaine) and now eating fermented sauerkraut daily.
I still have gut issues, but that part of me is soooooooo much better.
Good luck.
And btw, put a wedge under your mattress so you're slanted slightly up; this helps with reflux. Oh, and I did try Prilosec for 1 day and it made me feel as if I couldn't burp. Very strange. As if my stomach was somehow frozen. Weird and uncomfortable. That did it for me. No thanks!