I hope you have not stopped looking

. That deer is likely dead out there, and you owe it to the life you may have taken and to yourself to give every possible effort to retrieve it.
I have been in that situation before on the last day of deer season....I shot a nice buck and knew I had hit him good, but there was no blood trail, hair, or any sign of a hit. I was so sure he was dead that I called the GW and said I would go out looking for it....he said it was fine as long as I didn't take a gun along. After A FULL day and a half of hard searching, we found my buck.....a 205 pound 8 point.
Start from the last place where the buck was seen, and do a THOROUGH grid type search. Start in small diameter circles, marking off points as you go. You may find nothing more than a rack and some bones at this point, but it is your responsiblity to at least give the effort.
Hoping for an update soon!