I Have Had Loose Bowels/diarrhea For A Week Now Ranging

I have had loose bowels/diarrhea for a week now ranging from black, to Dk cream, mustard color and clear mucus Y then black again with slight amount of blood. How can I stop this? My father had colon cancer and needed a colostomy, lived six years and passed away at 65. I go for regular colonoscopies and am due this year.
My doctor said it should stop in five days, but today is the eighth day.
Please help me!
Thank you, Ardith Joy