you need to see a doctor. That is not a good sign. You could be having some serious problems and the yellowing (called jaundice) is a sign of malfunction. You may want to note if other parts of your body are turning yellow, like your nail beds, or your gums.
Preface this with: I am not a doctor...I only do volunteer work at a hospital...and study...
Sounds like you need to go see a doctor as soon as possible. Sounds a little bit like a liver issue...don't want to mess around with waiting!