Summarize this article in one sentence.
People do not always leave others out on purpose. Sometimes it just happens and it is not meant to make you feel bad. For example, you might have been left out simply because there was a missed communication, such as a lost letter or unsent text message. Or, you might have been left out simply because the person was not thinking clearly and she might feel really sorry for leaving you out. Being left out can cause you to feel lots of different negative emotions. For example, you might feel sad at first and then become angry and jealous. These emotions are normal, but they will pass. Instead of denying your emotions, give yourself some time to feel them. Sharing your feelings with someone who cares about you can be helpful. Try talking to a parent, a good friend, or someone else who you feel that you can trust. Explain what happened and be honest about how it made you feel.   The person who you share with may be able to tell you about a time when he or she was left out and may even be able to give you some advice about how to deal with your situation. If being left out has been an ongoing problem or if you are experiencing distress as a result, then you may want to consider talking to mental health professional. If you are still in school, then you can talk to a school counselor. If you are no longer in school, then you can find a therapist. Journaling has a wide range of physical and emotional health benefits. It can help you to understand your feelings better, reduce stress, and improve your ability to solve problems. To use journaling to help you deal with being left out, get yourself a journal or notebook and start writing in it for a few minutes every day. Your first entry could be about being left out. You could describe what happened and how it made you feel.

Summary:
Consider the possibility that it was a mistake. Acknowledge your emotions. Talk to someone about how you feel. Write about your emotions.