Hello I share your concern Bloody or black color stools is a matter of concern I see patients with similar complaint in my clinic, I would advise them for a battry of tests like blood for hemoglobin, CBC, Liver function test, coagulation profile like BT CT and prothrombin time and an endoscopy if need be. in my opinion you should immediately consult a gastroenterologist for physical examination and endoscopy to establish a cause of bloody stool Meanwhile you should take antiacidity medicines like pantoprazole or ranitidine group of drugs with antacids you may require iron or multivitamin supplements or infusion to meet the blood loss. Hope thsi answers your question, please feel free to ask for further assistance, I will be happy to help you Best wishes