Don’t wait! Resist getting sad. Get up now and go look. Start where you saw your cat last. Look in every corner and look in every space. Walk your way in a spiral direction from where you saw the cat, checking every space no matter how small. Open up cupboards, sheds and cars. Do not tell yourself your cat wouldn’t do this or that. Don’t listen to anyone who tries to discourage you. Most lost pets are found very close to where they went missing. Hurry up! Your cat might need medical attention. She/he is waiting for you. Cats are territorial and stay where food is available. Try again at night when things quiet down.
I have personal experience with this and so does my neighbor. Also there is an epic story of a cat lost and found at a ranger station in the wilderness. Ask me after you report back where you have searched.
But right now, start looking please!