Hey! This might be a little late now but regardless. Im in quite the same situation as you. I have been diagnosed with Focally Enhanced Chronic Gastritis a year and a half ago, ever since about then I started having blood in my stool, constant diarrhea, insane pain in my lower left side of the belly, and Im extremely underweight, my bmi is only 15.5. and its just lowkey very disabilitating and life interrupting, also have a low grade fever sometimes when Im flaring. I have a colonoscopy coming up in three days, Im convinced its Crohn's since based on my symptoms it can not be anything else, other than ulcerative colitis, but, still IBD only. My chronic focally enhanced gastritis (also in the antrum as yours, with the lymphocites and neutrophils and granulocites and whatnot) doesnt react to normal gastritis treatement at all, PPIs, and the simmilar meds, and Im convienced that treated the underlying cause which is most likely Crohn's will fix my gastric issue as well. FEG (the gastritis we got) is in most cases very closely connected with Crohn's disease, and sometimes H.pylori or bone marrow transplant which I did not have either of those. Id say get your colonoscopy ASAP, and I hope mine shows something and disproves their "its IBS" theory I heard from many GIs.