They thought I had appendicitis as well, took it out and sent me home. They said that my appendix was only mildly inflamed but it made my colon very inflamed so they had to take it out. Later, I told the surgeon I still felt awful. He said it was the antibiotics I was on. Several months later, and a different hospital, I was dx with Crohn's. Obviously my colon made my appendix slightly inflamed, not the other way around.
A colonoscopy with a biopsy is the best way to be diagnosed, and like DJW said, it never hurts to get a second opinion. Its your body and your health, it is important that you have all of the correct facts so you can make an informed decision on how to treat your body. I know you are over whelmed, but just take it one day at a time. Thats all any of us can ever do.