It turned out that I also had high levels of h.pylori and campylobacter. A
Prevpac took care of that. I also took a med called Xifaxin (for e.coli and parasites) and it helped too.
Sorry for the long winded answer. In my case, the answer was complex. But it could be as simple for you as a side effect of a medication. Many of them cause stomach problems if taken without sufficient food. (For me, Rifampin caused me additional stomach pain and heartburn, even when I took it with food.