D.J.
This sounds very much like what my 20 month old has been experiencing the last couple of days. My husband just had a virus that lasted about a week or so and the symptons seem very similar..... not very hungry, and just generally not feeling well. He also never had a fever. Right now I'm assuming that my son has the same thing, but if it doesn't clear up in a few days I'm planning on taking him to the doctor. That would be my advice...give it a few days and see where he's at. Good luck!
Updated
This sounds very much like what my 20 month old has been experiencing the last couple of days. My husband just had a virus that lasted about a week or so and the symptons seem very similar..... not very hungry, and just generally not feeling well. He also never had a fever. Right now I'm assuming that my son has the same thing, but if it doesn't clear up in a few days I'm planning on taking him to the doctor. That would be my advice...give it a few days and see where he's at. Good luck!