Well I'm not sure, we aren't supposed to suggest or promote medication, but i'm going to suggest/ask if you've tried something like quetiapine or it's also called seroquel. I'm not a med promoter, I actually wish I could go back and manage life without any medication. But that is one med that will help you sleep, and quiets the mind somewhat, only my experience that I can relate to you.
You must forgive yourself. Whatever it is cant be changed, it is in the past. You have to let it go for your own sanity, for yourself to be able to live in peace. Look at humanities history, the cruelty, tortures etc. and horrible people we know of now and major crimes being committed daily..... do you think you deserve that much punishment for a mistake in the past as these other humans do? I don't think you do. You need to be kind to yourself now. I don't know if we can recommend people that teach, but I'll take my chances. Eckhart Tolle is on youtube. You could type in Eckhart Tolle "the end of suffering." He has helped me, it may not be something you like but try his videos and see what might happen. best to you always