Tired...Always Tired

I've been quiet around here lately.  I have been spending the kids' nap times (when I would normally blog) just resting.  There's no obvious reason that I should be so tired.  I sleep an average of 8 hours at night - uninterrupted for the most part thanks to kids who are good sleepers.  We eat healthy, balanced meals.  I've been exercising.  I'm not sure what in the world is wrong with me, but my system is apparently lacking something.  Thanks to the nagging :) polite reminders from my mom, I've been taking multivitamins every day, but I am still just functioning enough to deal with the necessities like feeding my family and keeping the house (fairly) clean.  But I want to feel good!  I want to do more than just function.

I have a doctor's appointment scheduled for the end of the month to see if we can figure this out, but in the meantime, please feel free to add your two cents in the comments.  I'll definitely take any suggestions into consideration!