If you need help knowing how to re-trap your cat feel free to write to me. I caught every single cat I've targeted. I don't want to necessarily post it in the open forum because I don't want to help people who want to catch cats to get them euthanized. I only want to help people who want to help cats.
One thing I can tell you is that if your cat is nearby setting out a food dish and bowl of water consistently will draw in the local cats and you can watch for your cat. You may want to do this in your backyard if the neighbors will be bothered by seeing too many cats around but more cats will notice more quickly a lot of times if you put it in the front like on your porch because the view isn't hidden by fences. I'd only stop this if neighbors complain or if you see other animals that are potentially dangerous like raccoons appearing too frequently. If you do this don't forget to knock on the hood of your car before you drive off in case one of the cats or some kittens have gotten under the hood.
Also I don't recommend doing this for more than a few weeks if you can't get them neutered or spayed due to religious or other reasons because it's not very responsible in my opinion to feed ferals that will produce more ferals and contribute to the overpopulation problem. I think it's ok for a few weeks to help you find your kitty again though. If your cat smells the food on another cat he or she might be able to find their way back to your house by following that other cat back.
You can also try calling for your cat a few times a day, especially early in the night when your voice might carry farther than in the day.
I don't know if your cat was microchipped or not but if they were then of course call the vet's office where they were chipped for information on how to list them as missing in the system.
Whether chipped or not you should also contact local shelters both kill shelters and non-kill shelters and possibly leave copies of pictures of your cat at each one with your contact information that can either be posted on a public board or shown to the staff.
Also you can put up lost posters around your area.