Deciding which treatment to go with.

I was diagnosed with Ulcertative Colitis 14yrs ago. I was taking Lialda for about 5 months and had a flareup so my Gastro changed me to Asacol 4 pill X a day. I have been taking them for about 18 days now. I am still having Mucus and blood in stool , No diarrhea or constipation. Last Wednesday  he put me on Prednisone 40mg 1x day. So I don't know if I have been on the meds long enough for them to help but I'm still having symphons. The doctors says he needs to go to the next step In which I need to decide to go with Remicade, Humira, or Imuran. All of these meds have side effects. The doctor never mentioned anything about a special diet which from what I'm reading is real important to getting the colon to heal. Does anyone have info on products to get the colon to heal or Which med.would be best from personal experience from using .
Your thoughts Please