I don't have anything to add to the excellent suggestions everyone has made, just wanted to lend my support...I can only imagine how you are feeling and pray that you will soon be reporting good news on this thread. The one time our elderly Boston Terrier went missing, on a dark and rainy night, she turned up at a neighbor's just down the road about 1/2 a mile. She slipped out of her harness/leash on her nightly walk as she'd gotten so thin and we had neglected to tighten it up. I think she got disoriented since she was partly blind and deaf and thus couldn't find her way back to our house.

I was in a complete panic, but it ended just fine. Don't give up!