This doesn't sound too good, Have you seen him since he left?
did he get out accidentally or is he an indoor outdoor cat?
have you posted pictures of him on lamp-posts, or in shop windows
Advertised in your local paper? all these things could help you to find him
wishing you luck in finding him, and sending Purrs that  you do or that he
comes home most of all that he keeps safe, I would also ring around your
local vets in case he has had an accident on the road.   Jean,P.