My initial thoughts are:
a.) Herx reaction - temporary reaction, worsening symptoms
b.) Some additives in culturelle or other probiotics that are not agreeing with you
c.) Some other change you've made (you mentioned something about going on and off of Rowasa)
d.) If you have hemorrhoids, which can occationally bleed
Hopefully with a process of elimination, something will become evident. Maybe you'll have good luck with pro-bio, which seemed to stop other ppl's blood and I believe it did the same for me. Try giving them a call, others have gotten a free sample out of it! Just wanted to throw that out there as another option.
Yet to ever go into remission, additional Flare-up since Aug 12th
Time off work since 10/17. Returned to work on 1/11 and doing much better.
On Lialda (2/dy), Probiotics, Fish Oil, Folic Acid, Alpha Lipoic Acid, Borage Oil, Iron