Are you having blood in your bowel movements? If you arent then it probably isnt ulcerative colitis but could be chrons or celiac. There was a time when the DR thought I had ulcerative colitis and gave me tons of meds to try. None of them worked. I finally did an "unconventional" stool test thru enterolabs.com and they dx'd me with having both of the necessary genes that produce celiac disease; however, all the tests the DRs gave me came back negative (colonoscopy and biopsies). Anyways the Dr at enterolab told me my results that he found and recommended I go gluten and dairy free. i did and 2 months later I felt like a new person. The diet is hard but is soooo worth it if it helps you out.
The diet could also help with depression, acid reflux, anxiety, and other like disease or ailments. I know this is another thing to think of but if your tests all come back negative or the DR says "I really dont know what you have but I think it is ..." then you might want to look into the diet. Feel free to message me or just respond to the post if you have any questions.
Hope for the best.
March 2005 Dx'd with Ulcerative colitis
Took: asacol, colazal, rowasa, entocort, VSL probiotic
2.14.06 Test results positive for gluten and dairy sensativity! (enterolab)
July 2006 normal c scope and biopsies
Taking: Wellbutrin 150 mg Ativan .5 mg as needed
Gluten Free Dairy free since May 20, 2006 and feeling great