Blood In Stool What Does It Mean To Have Pinkish Blood In Stool?

What does it mean to have pinkish blood in stool? - blood in stool

Had some form of pink-brown stains in my underwear for some reason (and I'm) on my period, then had diarrhea, and not like the pink blood in my stool. there was not much, though. is a serious matter? What could be causing this?