Thank you both so much for your response! You have put my mind so at ease! Havve an excellent day!
I want to say, that black tarry stool is also a sign of bleeding from the stomach or upper (esophagus). Stomach bugs usually don't cause stomach bleeding. If you previously had gastritis or stomach ulcer, or if you've been taking aspirins, ibuprofen, a lot of alsco...smoking, than it could be blood. You will know. If any doubt, have a hemoccult test for blood in stool.
Black stools are TYPICAL after taking Pepto-Bysmol. Stop taking it and wait for few days, it should go away without any other measure taken.