I'm presuming you've had all the relevant tests done? Blood/stool tests, colonoscopy (with biopsies taken), CT/MRI scan, pill cam, etc? If not, you need to get those done ASAP. With Crohn's, you have to rule out disease in the small bowel as well as the large one, so if you have a clean colonoscopy, make sure you get a small bowel test done as well - the pill cam, or capsule endoscopy, is currently the best method for visualising the entire bowel.
Your symptoms do sound like Crohn's, but they could also be colitis (there are different types of colitis, not just Ulcerative Colitis) or a bacterial infection - there are a few which mimic Crohn's very closely. (If you want to know more, read this article
If you can't persuade the University of Pitt. doctor to take you seriously, seek a second opinion. Fevers and watery diarrhoea indicate something else is up besides IBS or chronic abdominal pain. Best of luck...