My Cosi isn't eating!

I have a dwarf bunny and I purchased him on May 20th of this year (2006). When I purchased him, the lady who sold him to me said he was only 2 weeks old. We brought him home and bought a decent sized cage, food, even a cute little bed and a potty training for him. We let him walk around the house for exercise and everything. Well, my mom told me that today he hasn’t eaten much because when she went to look at his food it didn’t look like he had eaten anything. Yet, I’ve seen him drink plenty of water. I’m worried because I don’t know why he’s not eating. This is my first pet that isn’t a fish so I don’t know much and I’ve just been asking questions and reading articles on the internet. If anyone can help me out I would really appreciate it! His name is Cosi, and my family and I have fallen in love with him. Please help…. :(

Did you say 2 weeks? That is pretty young for adoption. Do you have a "salt lick"? Small animals need salt in their system. NOT "table" salt. They sale salt licks in the small animal isle. Cosi could use that.
Does it have a water bottle or bowl? You may add some liquid vitamins to the water bottle in case of malnutrition is suspected. Give some baby carrots to gnaw on for their teeth. "Hay" may be a good thing too. It is sold in small bails at the pet store.
I would also suggest because of it's age, to give it some "cat's milk". There are small packages of milk available to give to newborne kittens. It's a "special milk" with no lactose in it. You may want to see if you can give the bunny a little of that. I wouldn't give it to it after it is older like over 2-3 months.
Cover the cage with a towel to block any possible direct air flow. Air conditioning is terrible on small animals. Also it may provide a place for the rabbit to feel like it is "hiding". They like cover.
I used to let my rabbits out for fresh grass once in awhile. Just keep a close eye on them! You can get leashes for them and they work if you train early! Good luck!