Shalom in Yeshua Kellie 69, I am sorry that you have been feeling this way for so long. You don't appear to have been able to share your feeling with anyone before. This is a great place to do that. Everyone here has been through what you are going through. We all understand and are all willing to help you.
Do you have any beliefs or faith in the next life? Having faith does help.
What happened to the boy who shot your son, and how are your other children coping? I will pray that you can come to terms with your tragic loss, but most important is that you keep talking.
God bless you