I have been there and I am very sorry you are going through this. It is possible to overcome those feelings. Religion helped me ( now I do not participate in the church anymore but I have to recognize that it was helpful in that regard). The only thing that helps me during times as described by you is not to take myself so seriously. Also, to acknowledge that I am just a tiny particle of dust in an immense universe and that I do not control everything. Yes, I own my decisions but there have been a lot of conditioning. I deeply think that we are not as free as we think. And that it is a temptation of pride to go to the past to beat up myself. I am not somebody that indulge herself with avoiding responsibilities at all. But there is no magic thought that will transport me to the past to modify a single thing. It takes a lot of thinking and discipline to stop visiting the past, but it is possible. Instead, it is the future what scares me and causes my depression somehow. I have not achieved the necessary mental discipline to stop that. But I am hopeful I will do it some day.