There are so many things that are good about writing. It helps with grief and trauma and general sadness. It helps in the short term and in the long term.
Trauma and the benefits of writing about it.
It actually helps with physical pain symptoms and causes a rise in immune system functioning. It's amazing.
Narrative Apparently it helps much more if you try to write your experiences as a story, as if you were telling someone else, rather than just listing things or writing randomly. Something about trying to put your thoughts in order to make it understandable as if to another person, helps in the process.
Find a private space and write. It will be hard, but it will help, both now and in the future and bring about that elusive posttraumatic growth.