In my opinion, your step dad was WRONG when he told you that you were a messed up little kid.  That is not the way to speak to any child.  I feel like I could have greatly benefited from therapy during my childhood.  There are pent up feelings, hurt, and beliefs I carry inside.  I struggle with self-forgiveness.  I have read numerous self-help, psychology, and mindfulness books, and still am searching for ways to forgive myself and move past past-hurts.

There is a guided meditation I listen to often called Forgiveness by Dan Ireland of Awareful.  I listen to it on an app called Insight Timer.  It almost always makes me cry.  I find it helpful.  Perhaps you would as well.

From your posting, it is clear you did not have it easy growing up.  You had the courage to get out of there and enlist in the military and serve your country.  You have the courage to post about your struggles here.  Give yourself a ton of credit for being brave.  I hope you are able to find ways to forgive yourself.