I Have Had UC For 20 Years And Have Been

I have had UC for 20 years and have been inactive for several years. Last year I had a colonoscopy that found a precancerous polyp and removed it. I am now having some mucus tinged with blood discharge. Some of the mucus has been greenish in color as well. I also am having abdominal pain on both sides, nausea, cramping, and painful stools. I am not having fevers. Do you think that this could be the UC flaring up again or something more?