It's good that you are reaching out for help. Finding a therapist you can sit with and talk these challenges out with that understands the kind of grief and trauma you are trying to work through is important. You may also benefit from doing a search to see if you can find a support group of individuals that are also dealing with a tragic loss like this.

I am so sorry you have had this experience, it's understandable that you are still struggling. We cannot remove traumatic life experiences, we have to grieve them and learn how to live out our lives in spite of these major traumas and it's a big challenge.