Sonnyboy,
I know exactly what you are going thru'. It has always been a big problem for me in my life. There are times where I gringe with regret when I remember some things I've done. At times, it can be all consuming. One bad memory leads to another, leads to a feeling of empty regret and worthlessness, then to a depressive episode.
Some things which help me :
Being brought up a JW gave me a skewed view of the world. It retarded me socially and emotionally. It also put me on a perpetual guilt trip. Acting irrationally, stupidly and unkindly were to be expected and all part of the learning curve to becoming a 'normal' human being. If you hadn't had done them you would not be the person you are today. The fact that they are so regrettable proves how far you've come.
After leaving the JWs at aged 18 I was on my own emotionally. There was no family support for my actions, no one to go to for help, so I was finding my own borders. You have to cross borders to know where your own are. Plus even people with normal upbringings have difficulty with this time of their lives. I worked at a restaurant when I was 17. The boss organised a staff party, JWs and non JWs. It started at 6pm. I was drinking the cooking brandy slyly and was mangled by 7pm. My parents were called to pick me up because I was so drunk. I acted like an ass and was made to feel really guilty - not because I made a fool of myself, but because I gave a bad witness. Skewed logic.
I always try to be positive. Look to the causes of your actions and figure out why the reasons why they were right at the time. Were your reasons correct but you unable to express yourself to get heard? Were violent actions the only way to get heard? I suffered with a lack of empathy. I'd barge into partners lives, take whatever I wanted and dump them, moving on to the next woman and it would happen again. No empathy had ever been shown to me by family or the congregation, no one really cared, so I never did, not thru choice, but it never occurred to me I was doing anything wrong.
You also cannot change the past. You are the sum product of your history, good or bad.
Try and dwell on successes. What is the best ever moment of your life? Try to relive it, feel your emotions, the physical sensations when it was taking place and how you felt afterward.
Memory is a deceptive tool. One persons memory of a situation is totally different to someone else's. I remember a wedding where cousins were arguing about what happened 40 years ago when they were kids. To hear them you wouldn't believe it was the same incident. Your brain corrupts the memory. You put a 'regrettable tag' on a memory and you it will intensify every time you remember it. Feeling bad about something that other people have forgotten about or didn't think was that bad to begin with is pointless.
I hope this helps.
Si
PS I'm going to regret this post aren't I? - :-))