Rectal ulceration. Or what is it?

For the last 15 days i  spasms(marod) in lower abdomen(sounds come,I can also feel them on touching),passing mucus mixed with blood in stool,did sigmoidoscopy which revealed Rectal ulceration(SRUS)..While passing stool,it does not clearly comes out,fullness near rectum but it doesnt come out clearly,then 15 minutes after passing stool i feel its not very clear,I feel spasms near rectum(even sounds come from rectum) and pass gas and after sometime,i go to pass stool.Feeling of heaviness  in lower abdomen and also sometimes pain,sometimes i feel that something is descending from lower abdomen(it is similar to what we get when we move a fillef water bottle only once)not much relief after passing stools..am using sucralfate enema for this(twice a day)...is rectal ulceration the reason behind my problems??or what is it??plz tell