Questions about poop

Yeah the topic is poop. I just had my perio and thought I had really bad cramps (from the bottom part of my boobs down to my stomach area) my poop was fine during that time and my cramps went away just as my period did but today (the day after my period stopped) my poop was black or dark green i can't tell and has been the past several times i'm gone today. Should I see a doctor about this? Is this normal?