I certainly don't know if it's common but I do know it's possible for CRP to be normal and still be symptomatic. I haven't been there, but my doctor has talked to me about it. It's hard to say what your next step is not knowing what you've tried. But, I am sure your doctor will work to treat the symptoms. Good luck!
--40 year old female, dx as UC in '04 (1st symptoms in '03), switched to Crohn's in '05, 1 fistula, crohn's colitis, limited to large intestine
--rejected (reaction/didn't work): Asacol, AZA, 6-MP, MTX, Remicade, Humira, prednisone
--methylpred - finally off 6/15/08, tried Prochymal in Phase III study (can't wait til it's approved!)
--started Tysabri 3/21/08, started Xifanan 5/24/08
--single mom to 10-yr-old girl