I've heard by my colon and rectom surgeon that stress can exacerbate CD symptoms, he told me to keep my life as stress free as possible and learn to deal with stress so it doesn't affect my disease as bad...stress is also a major trigger for Ulcerative Colitis and IBS.
Here's a link, "stress can be bad for your bowels"...
http://aapgrandrounds.aappublications.org/cgi/content/extract/16/5/56-a