Search every nook and cranny of your house and grounds on the chance that your pet has become caught or trapped or is sick or injured and hiding. Do not assume they will meow or bark or come to you. Cats especially are likely to hide. Look in closets, drawers, air ducts, behind appliances, under beds, in the hollow under reclining chairs, behind books in a bookcase, wrapped in the bottom of drapes, in any hidden recesses, basement crawl spaces, in sheds, garages, under decks, in pipes and culverts, dumpsters, garbage cans, etc. Cats also have an unfortunate tendency to explore new places, like the back of pick-up trucks and they often get accidentally carried off. Consider whether there were any vehicles around that your cat may have hitched a ride on.