I definitely know how you feel. A couple of times, my dogs went missing for days and I couldn't function, either. There is hope - sometimes, they just show up again. Sometimes you need help. I'm sure you've done all this, but make sure you call your local shelter every day - who cares if they get sick of you, at least you know they'll be looking at every single dog that comes in so they can get this crazy, annoying lady off their backs.
Put an ad in the paper (with a picture if you can afford it), hang posters all over, offer a reward (you don't have to say how much it is, just put REWARD on the poster), contact all the vets in the area - put a poster up at each vet office too - in case someone finds him and brings him to the vet to get checked.
Call the radio stations - sometimes you'll find a sympathetic DJ who will put the word out on the air (if you have kids, get them to do it - who can resist a child mournfully looking for their lost pet)
And, we will all be praying with you that he will find his way home safely.
Jeanne