Not long ago I experienced bleeding in my stool. It was when I wiped it was red on the tissue. I haven't had any pain since or noticed any bleeding since (this was around a week ago).
Tonight I went to the toilet again and it was almost black diahorrea with a bad smell and i'm not certain but think there may have been blood through it but i can't be sure if i'm imagining it.
What could this be and what should i do?