Gosh, I really feel for you! I think you'll have to go cold turkey and I hope it doesn't last too long. I hope that he's soon sleeping and eating normally and you won't have to worry about when your baby comes along. Can you maybe give him a substitute toy, like a teddy or something (maybe a wizard teddy)? OK, not a great substitute at first but at least it's something new to keep his mind off things.

Good luck!