likely you are suffering from ulcerative colitis
or a indeterminate disease
the symptoms suggest you are having tenesmus
due to rectal involvement
in such case a stool examn, sigmoidoscopy
will confirm same
if rectal inflamm is there changing doses and addng medication enema
Hope this answers your query. I will be glad to answer the follow up queries that you have.
Please accept my answer in case you do not have further queries.
Wishing you good health.