I was just reading Tony Robbins Twitter message for the day, "The weak can never forgive, forgiveness is the attribute of the strong-Mahatma Gandi. What freedom can you experience by forgiving today?" This lead me to google the word "Forgive" and I found a website that had many suggestions on how to forgive and two of them really stood out:
Make a list of the good things that emerged as a result of this awful experience. You've probably focused long enough on the negative parts of this experience. Look at the problem from a completely new angle; look at the positive side. The first item on that list may be long overdue because you have focused on the negative for so long. See if you can identify 10 positive outcomes of this experience.
Look for the helpers. Fred Rogers (Mr. Rogers) related that, as a little boy, he'd often become upset about major catastrophes in the news. His mother would tell him, "look for the helpers." In your own nightmarish experience, think back to the people who helped you. Think about their kindness and unselfishness. Practice what you have learned from them.