Fatigue is my biggest problem as well. Sometimes I chalk it up as a side effect to whatever treatment I'm receiving: chemo therapy or chemoembolization; but I was tired before treatments too. For instance, today I slept from about midnight until 1PM and still needed to take a rest on the couch around 7PM or so. I imagine I'll go to sleep around midnight as well.
Talk to your doctor if the fatigue is overwhelming/debilitating. I've been prescribed two different drugs to combat it - Provigil, which did not work for me (but might for someone else) and Ritalin (believe it or not) which does seem to help a bit.
Other than that, I think it's just something we'll all have to deal with...
Best of luck