Today, I was sad to go to the toilet and when I went, I had diarrhea and black stools. My period is now 5 days late. I used to go to the doctor and learned that I had antral sphincteric congestion, took medicine to treat it, but it was gone from 5 months ago. Due to the epidemic, I could not carry out the follow-up examination as scheduled. I only have abdominal pain and black stools, other than that there are no other symptoms. Doctor let me ask, diarrhea, black stool is a sign of what disease?