Collagenous Colitis with constipation?

Hi I am 24 year old female. I have been experiencing my symptoms for about 8 months now. I started out having pelvic pain and pressure that radiated to my lower back with some abdominal cramping and a feeling of tightness in my stomach. As time went by the pelvic pain/pressure faded and the abdomial (abdominal) pain took over along with back pain. I had pelvic ultrasound and papsmears to rule out most female things and I then had a CT with contrast and a MRI. Both showed nothing. In the mean time I had been suffering with some constipation. Finally I had a colonoscopy which showed internal hemorrhoids, and some irritation in my colon. Biopsy was taken and it was concluded I have collagenous colitis. I was put on endocort and diet. I have been on that for four weeks and NOTHING has changed. I still have constipation, abdominal tightness/bloatedness that radiates to my lower back and causes it to ache. My question is could I have something else besides collagenous colitis? Should i even be having constipation if I have collagenous colitis? i am searching for answers and would appreciate some input.