Even survivor families of murdered people struggle but eventually have to move on and rebuild their lives. Your continuous suffering does not bring them back. Your eventual happiness does not disservice the loss. That's the hardest part of grief and injustice.
Feeling angry at the event is normal, but if it is crippling your ability to take care of yourself or others who depend on you. Then that is what is unhealthy. Holding on to the pain and anger to the point that you don't function properly is actively hurting you further.