Donna, I really feel for you! I'm getting emotional thinking about it!

If you don't find him tongiht, I would put up posters throughout your building and neighborhood. You should also check local shelters in case he was hurt and someone took him in. Most cats will stay in the immediate area, very close, when they are out of their natural environment. I still would put your scent our there to attract him (ie: sweatshirt) and some food.

Also, look at this website that has tips on finding lost animals:
http://catsinthebag.org/

But that is IF you don't find him tonight. You may very well get him home tonight. Keeping fingers crossed and keep positive!! Negative thoughts do nothing but eat away at the positive ones!!