I feel for you man... but here are things to look out for:
1. Look at nearby air ducts/drainage pipes/etc. - sometimes cats fall and get stuck in them
2. Look throughout the neighbourhood, sometimes (if the cat is in heat) they will wander off and forgot how to get home. They will hide somewhere safe and only approach if someone they know are near.
3. Was she an outdoor cat? If she is an indoor cat she will have gotten lost. Indoor cats are pretty bad at locating where they are. They will nearly always look for safety and hide if they do.
4. Cat impounds. If she wasn't tagged in any way, she probably was taken by the police to a cat shelter.
Yes, yes I'm back.
Somewhat.