I don't have a solid formula on how I lift myself up from the misery of the situation. All I know is that I sulk for a bit to get it over and done with, then I stop and decide that my sadness has got to stop. It's not as easy as a snap, of course. It takes a lot of convincing myself that it has to stop.
Of course, that doesn't always solve the problem. So the next thing is distraction, a big one. I watch rom-com movies, anime, read books, talk to someone, look at funny stuff (LOLcats, anyone?) - anything to get my mind of it. It is not running away from the problem at hand. I just know that if my mind and heart are calm, if not think of a solution, I could at least cheer myself up.
I believe in the power of positive thinking. So it is so important that I always have something positive to turn to, to hold onto at any given time. This is one the positive thoughts I make sure I remember. Trusting your hopes materializes them into reality - that's what you need to know. Or it could be the simplest thing like ice cream or a cup of coffee (both are like a big hug for me) or the biggest part of my life, God. I turn to Him and pray, read His Word or my fave bible verses. I pray and pray and read and read until I feel I'm overdosed with hope and trust in Him. That's when things really start to look up.
Actually, that should also say,
Trust in God, not your fears!