I think you're making a big mistake by posting this here. Any good prosecutor will use this against you.
Have you contacted a criminal defense attorney yet?
I can hear the trail lawyer now:
Clearly this was a "Bad Shoot". The deceased (the son of my client) was un-armed and clearly trying to escape. He posed no threat to your or your family and was only trying to feed himself. You say that you carry a loaded gun in your pocket while in your house? What are you paranoid? You drew that loaded gun, that you say you were protecting yourself with and shot my un-armed son of my client who was attempting to run away! What threat did he post to you?
Clearly I was joking!
Good shoot. It sounds like a great training opportunity. It very well could have been an evil-doer.