A breakup of a friendship can be very difficult since a person tends to get emotionally invested in her friendships, says Irene Levine, a psychologist cited in the article, "A Friend Is Someone Who Likes You Vs. Viet' Nam, Viet' Nam' When Friendships Go Bad" on the Huffington Post website. Unfortunately, friendships end for a variety of reasons, and can leave you mourning the loss of your friend. During this time, it's important you take steps to grieve and to move forward with your life.

Confront Your Pain

The ending of a close friendship is no different from the ending of any other long-standing relationship, says Melody Wilding, a therapist and author of "Surviving a Friendship Break Up" on the PsychCentral website. You may feel intense hurt, bitterness, anger, guilt, sadness or any number of various emotions. Don't try to ignore your feelings. Wilding suggests allowing yourself to experience your hurt feelings and to cry. As you go through the grieving process and accept your loss, your pain will lessen in time.

Make Other Plans

When mourning the loss of your friendship, fill the space with new activities, suggests Therese J. Borchard, author of "8 Steps to Closure When a Friendship Ends" on the PsychCentral website. This can be a good way to move on and to have fun. For instance, join a kickball league, participate in a book club or learn how to cook.

Compose a Break Up Letter

Writing a letter to your ex-friend can be a very therapeutic means of expressing yourself, says Wilding. Composing a "goodbye" letter is a way to communicate your feelings, say the things that were left unsaid, and ask the questions that were left unanswered. While this can be a great way to get everything off your chest, remember that this letter is for your eyes only.

Remember Your Positive Attributes

It's not uncommon for a person mourning a friendship to blame herself for the breakup, says girlshealth.gov in the article, "Getting Over a Break-Up." Blaming yourself is not going to do anything but make yourself feel worse. Rather than focus on what went wrong and pointing blame at yourself, think about your positive attributes. For instance, you might have a sympathetic heart, an upbeat personality or the ability to put others at ease.