To go through life in fear of the unknown is not the way to live. To live with action that will make a positive difference is what time is for. Smile often and show a caring interest in those around you. Go up to that student who is sitting alone in the cafeteria or classroom and say hello. Say please and thank you, and be willing to do what you can to make life better for others.
Time is a precious mystery.
Spend whatever time you have left being as useful as you can, so when it's finally over there will be no regrets.