Staying Calm When Lost
How to Keep Your Cool in a Not-So-Cool Situation
T is for Think - Ask yourself how you got there and how much time you have before dark.
O is for Observe - Try to identify your surroundings. Look for possible shelter, food, or water.
P is for Plan - Decide based on your prior knowledge of your situation and your observations whether you should stay put until morning or try to make it out to shore (if on an island). Plan out how you will build a fire for warmth, eat, drink, and provide your own shelter.