Fatigue is a very common symptom for Crohn's but for many different reasons depending on the case. It can be due to the anemia induced by blood loss, constant diarrhea and/or dehydration by itself or as a result of diarrhea, lack of appetite, malnutrition, and the general strain the disease puts on your body for a number of other reasons. Rest definitely helps, as well as making sure that the right vitamins are taken, lots of water(though it is hard to get it down sometimes), really careful watch over diet, and not overdoing it.
Just a few suggestions anyway. In any case, it's not uncommon for someone with Crohn's to be very tired. We just have to do our best to live with it and work around it without harming ourselves--like overexertion or eating the wrong thing.
20 years old, Diagnosed with severe Crohn's and colitis in May of 2008.
Prednisone, pentasa, alinia, bentyl, prilosec, tandem plus, and the occasional ultracet
Surgery for ectopic pregnancy(very possibly due to Crohn's inflammation) in July of 2008.
Due to start Imuran September 17 depending on blood results.