Im In The Process Of Getting Over Being Sick. (I

Im in the process of getting over being sick. (I had diarrhea and threw up once...had some major gut rut and naseau). I took pepto bismol once a day for two days and it helped settle my stomach. I also didn't have a bowel movement for those two days. Today was my first bowel movement since the pepto and it was green initially and now as the day progressed, it has become darker. Is there a cause for concern??