Talk to Gastroenterologist on Ulcer Near Anal

Hello, its an urgent query. There's an ulcer of almost 1cm (or a bump) near perineal area (anal). It is related to my stool i guess because whenever i pass stool it increases and filled with puss which is very painful and irritation and there is a continous pain in that ulcer. I can't able to walk or sit properly whenever it increases. There's also a drops of blood everytime i clean. I don't know what is this and who to consult please guide me. Its been here for like 1 year at the same place