Ulcerative Colitis. To me correct?

I have been diagnosed with Ulcerative Proctosigmoiditis for the past 6-7 months and have been under consultation with a Gastroenterologist Doctor here in my home town. He has prescribed me Mesalamine Tabs (1.2g) and Mesalamine Enema (Daily, or when there is severe pain) along with some Folic Acid Tabs. Even after consumption of these medicines, i do not feel much of a change or reduction in Abdominal Cramps and pains i Experience during Bowel Movements. I have around 2-3 Bowel Movements a day of which most of the time Stools are Accompanied with Blood. Gas Discharge also occurs during normal time which interfere with my Daily life. I am an Electrical Engineering Graduate currently Working as an Apprentice at an Electricity Board. So doctor Could you Please answer my following Questions?: 1) Is this disease curable? although surfing through the internet says no cure has found yet! 2) What is the reason Behind the occurrence of this Disease? 3) Are the medicines Prescribed to me correct?