Like the first person who commented said, it may be that yours has gone so long without eating that it's made itself sick. A friend suggested this to me, and it worked on mine when he wouldn't eat as a baby. For the first few months I had him, I would give him a warm water bath every two days for about ten minutes (he had some pretty severe impaction issues), put him back in his cage, and immediately give him a cricket or two, and he'd eat them right off. I don't have to do that anymore, but if you can establish some sort of routine like that, or even try feeding him in a separate tank like some people do it might get him started eating again.