severe abdominal cramps, mucous and blood and distention

I am a 34 year old female who has, for 5 months, been experiencing severe cramping in my lower abdomen, bloating and excessive distention, and blood and mucous in my stool. I have finally been seen by a specialist who did a sigmoidoscopy and found inflammation close to the rectum. He is treating the inflammation before he goes ahead with a colonoscopy but is throwing out a diagnosis of ulcerative colitis; however, the absence of one of the main symptoms, diarrhea, leads me to believe he's not right. Also, the pain seems to get worse close to my period and then I can't tell if it's coming from the bowels anymore, or if it's the uterus, as the pain sometimes radiates down my back and vaginal canal. There just seems to be so many different areas where the cramps come from, it's hard to find any comfort in what a doctor says anymore. Also, for the past 2 weeks, my occipital lymph nodes have been swollen and sore.

Help! Anyone else have anything similar?