Thank you for asking this question that will benefit a lot of patients.
It is very terrible to have to undergo a traumatic experience. It is important to seek treatment as early as possible as it can lead to other mental health and physical health issues.
The mainstay of treatment is still psychological, or "talk therapy". There could be many treatment types within psychological treatment. But the first step is getting yourself to the room of a trained clinical psychologist. These people should have a post graduate qualification in clinical/counselling psychology.
Once you are there, the psychologist might use the following:
1) Cognitive behavioural therapy
2) Eye Movement Desensitization and Reprocessing (EMDR)
3) Mindfulness and relaxation therapy
Or combinations and many other effective treatments.
And of course if all else fails, you might need medicatons.
Take care.