Ok first, when ever po pull shit like that, get a lawyer. Obviously to late for that, but you still need to get one. An affadavit doesn't mean shit if you were coerced into signing it, and it sounds to me the only "proof" they have to go on is your confession. Even a halfway decent lawyer should be able to get you off w/ nothing more than community service.
Also, thats some BS about killing deer, what is this, 14th century england?