Two things struck me reading your comments
akindrat18, firstly; I had black poop when I had bleeding peptic ulcers along with awful stomach pains. I was also throwing up blood spattered vomit (sorry to be so descriptive), but I am assuming the hospital will be all over that. It seems such an obvious possibility. I can also shout up about gluten intolerance too. I had been iffy with gluten for ages, but a few weeks ago it suddenly ramped way up and now I can't tolerate any gluten at all. Even a couple of regular bread crumbs will trigger me to cough until I vomit. Coughing, bloating, IBS, acid reflux, stomach ache, constipation, diarrhea and pooping 10-15 times a day are my gluten intolerance symptoms. I stopped ALL gluten in my diet and the symptoms have subsided about 90%. If I glutenize myself the effects are immediate, coughing, nausea and acid reflux, followed by bloating and two or three days of alternating constipation and diarrhea multiple times a day. You are in a good place (well the gluten thing at least) for testing for Coeliac disease (CD) because you are still eating gluten. They can test for the antibodies. I'm not because I will have to start eating gluten again. I'm currently waiting for results for the genetic biomarkers for CD. If they comeback positive I will make a decision to take it further and start eating gluten for several weeks to test for antibodies. It's a big decision because the outcome is till the same, cease ALL gluten in my diet.