How can I stop feeling like killing myself?

Every morning for the past few months I've woke up contemplaing suicide. I even have a fail-safe plan on how I would do it. I've also convinced myself that everyone would be better off if I were dead as opposed to me living. I barely live as it is. I sleep for as long as I possibly can. I don't work. I doubt my ability to do or accomplish anything. I even understand how silly it is to think like this, but it seems to be my natural response to everything. I tried killing myself before and was hospitalized, had psychotherapy, and even that didn't help. I'm convinced I'm a waste of life, even though it isn't true. Or at least it isn't true to anybody else, but I feel ashamed about everything and suicide seems rational as crazy as that sounds.