What could be causing me to have a dark brown discharge an bleeding?

I'm almost 50 years old an i have been having this real pain in both of my right an left sides, an the pain goes into my back. it hurts so bad i have to sit down an i have this dark brown discharge an bleeding from my private area an i can feel it when it comes out. I have to change my underwear because they get wet. also i can't hold it when i have to pp. also it has a smell ot it i cant describe it. an i don't have my periods anymore i had a hysterectomy back in 1999 becuz of bleeding an i was getting pre-cancer cells.