All life is a losing battle, the trick is to let the body wear out before the mind, and perhaps make the body last as long as possible.
Have you tried CBT, suffering with an ordinary existence either means you aren't recognising the trauma you have actually suffered, or your thought patterns are not healthy, thats where CBT comes in. Repeatedly following specific thought patterns strengthens the parts and pathways of your brain responsible for those patterns, and as most things in nature follow the path of least resistance, our brains use the strongest pathways to process things unless we make an effort not to. CBT is about training you to use different thought patterns to hopefully train new, heathier pathways. It is a long and uncomfortable road, but can really help, and should get easier as you go.
As for the things you have done, I also have a list of things I will never forgive myself for, and if I am ever asked to take account for those things, I will accept what is coming, but until then, you cant change the past, you can only improve the present and the future, so it is best to try to put as much in the plus column as possible, not for your own sake, but so that you are a net positive to the world. There are too many net-negative people in the world, who cause more harm than good, if you have the presence of mind to see you may be causing more harm, then you are one of the rare ones who can deliberately choose to do good.
Remember, all life is a losing battle, the trick is to make the world really work for its win, to live as long and as well as possible.