According to the symptoms you describe (light abdominal pain with little diarrhea), you could be experiencing a gastrointestinal infection. A microbiological examination of the stool is necessary to identify possible causes of an intestinal infection. Pain in the rectum/anus while having bowel movement can be due to some local lesion like fistula, fissure, inflamed hemorrhoids etc.
Stress and anxiety can also manifest as gastrointestinal symptoms (diarrhea, constipation, bloating, abdominal pain etc.). That is so called irritable bowel syndrome (IBS).
You can visit your Primary health care provider if the diarrhea continues in order to request diagnostic examinations and consultation.