Take some time to reflect on the difficult situation. If you're having trouble finding a positive manner of thinking, just start by smiling at yourself in the mirror. You might not feel happy right away, but it sure will be hard not to feel happy when you see a beautiful smiling face staring back at you!
You can also consider the use of positive affirmations to help you through tough times. The more frequently you repeat your affirmations, the sooner you'll ingrain the positive beliefs into your subconscious.