Hi and welcome and congrats on the pregnancy :)
I agree with the others, it will take some time for the colon to heal. I noticed improvement quickly with Rowasa but it took a few weeks for blood to be gone. Also, with pregnancy, beware hemmies, that could be a cause of blood as well, I know I had them during pregnancy but not often otherwise.
Hang in there, don't taper too quickly (mistake I made). Be patient and let the meds work.
Best of luck!!