It sounds like you could have an abscess or a fistula. I would get in touch with your GI. I had a perianal abscess, had an operation to cut and drain it, and two weeks later was having lots of discharge vaginally. I went to my primary care, and he looked but didn't see anything (anally or vaginally). I went back in a week later because it was getting worse and I had a fever, and another doctor saw it. Then it showed up on the cat scan. If you have a fever, that can be a sign of infection as well. If it is a fistula, you most likely have CD instead of UC. My original dx was UC until this fistula happened.
CD 2010, Fistula, Pancreatitis
Prednisone, Imuran, Asacol, and Remicade
"Wherefore, whoso believeth in God might with surety hope for a better world, yea, even a place at the right hand of God, which hope cometh of faith, maketh an anchor to the souls of men, which would make them sure and steadfast, always abounding in good works, being led to glorify God." Ether 12:4 (Book of Mormon)