hmm hard to say, I agree with earthmama. I'm not sure if eating disorders start that way and just hit all of a sudden, and most people don't notice right away that they are eating differently. So perhaps you are getting sick.
But you've got me stumped. Just see what happens over the next few weeks and if this uninterest for food keeps going on. I also recomend checking with your doctor. If it is an eating disorder its better to catch it early on for an "easier" recovery.