What word means "to feel better by writing it down?" Usually speaking about your emotions.
Catharsis is (Dictionary.com)
- the purging of the emotions or relieving of emotional tensions, especially through certain kinds of art, as tragedy or music.
See, for example, Why Write? Catharsis, by Amber Starfire, May 2010.
Perhaps the most obvious benefit of keeping a personal journal is catharsis. The word “catharsis” originates from the Greek language and means to cleanse or purge...
Vent is (Dictionary.com)
- to relieve by giving expression to something
See examples at I write to vent my frustrations.
A word you could use is journaling. As this article from stress.about.com says:
What Is Journaling?:
Journaling is a term coined for the practice of keeping a diary or journal that explores thoughts and feelings surrounding the events of one’s life. Journaling, as a stress management and self-exploration tool, is not the same as simply recording the happenings in one’s life, like keeping a log. To be most helpful, one must write in detail about feelings and cognitions related to stressful events, as one would discuss topics in therapy.
Also take a look at this article from psychcentral.com : The Health Benefits of Journaling
However, 'journaling' could also be used in a generic sense- like maintaining a regular log, that doesn't really have much to do with stress-busting.