You can get out of an unpleasant situation with minimal losses.
General rules
Do not panic! You and your loved ones are alive and well. Lost is just a thing. Unpleasant, but it's not a disaster.
Look for a better one. Turn out your pockets, feel the lining of clothes and bags. Reproduce your route, remember the places you were in, the people with whom you spoke. Often the keys are, you just have to calm down and think a little.
Remember, there is a spare kit. Keep a duplicate of keys at work, at the cottage, at parents or friends - a sign of prudence. Ponder whether you showed it once?
Declarations about the loss of keys are a bait for criminals. It is not necessary to talk about what happened to neighbors on the porch or parking lot, and especially to blow in social networks.