It's a possibility your diagnosis may have changed from Crohn's to UC if you've just been diagnosed with Ulcerative Colitis and Proctitis. But, I'd contact your doctor and ask them to make sure.
I know that before I was diagnosed with UP I had a different doctor that told me I had Crohn's too. But, this current GI of mine told me no. It's Colitis and Proctitis.