Diarrhea every day for 8 days after surgery

[Ct9393]

I had abdominal pain last week and had a CT scan which showed it was an ovarian cyst. I had it removed and have had diarrhea for 8 days straight now. It started out very frequent and painful (every five-twenty mins- about 20-30 bms per day) and it has gone down to about 6-8 per day but the diarrhea is still dark and sinks to the bottom. I naturally have had a sensitive stomach in the past, but never diarrhea for this long. Immodium has not helped and neither has bland food. Has anyone else experienced something like this after a surgery? I had a little diarrhea before the surgery too so I didn't know if this could be a bad reaction from the CT Scan fluid (I had to drink a liter of it and never have had it before). Should I go back to the ER? Thanks!