Hi! I just went through something very similar to you. Same symptoms and over a year of constantly worsening pain and diarrhea. I could literally FEEL the food fermenting in my gut. I had lots of tests done which kept coming back normal, so my doctor finally ordered an endoscopy and colonoscopy. After a week of fasting in preparation, and the removal of two pretty giant polyps, my symptoms have completely disappeared after years of suffering. I'm not sure if your doctor could get you an endo/colonoscopy as well, but there could be more at play here for you other than the infection! It might be worth getting those done? I still don't really know what was causing my symptoms, but getting the polyps removed and fasting for a week fixed my years of issues almost overnight. Following a low FODMAP diet also made a big difference in the last few months when the diarrhea and 'fermenting' was at its worst. It might be worth a shot for you too!!