I doubt there is too much others can due on the great and wide internet. You might seek some other help. This could be in the form of a mentor, therapist, Priest, Pastor, Rabi, Imam, local support group or other source.

That aside, it is possible, but it is not easy. It certainly is possible to dramatically in a short amount of time improve you current outlook your can get start with the following but this is not a replacement for some outside assistance. First, stop thinking of your self-defeating thoughts so much. You likely spend a great deal of time dwelling on how horrible you think you are (unlovable, helpless, unlovable, inadequate etc...), you will need to stop feeding those thought by recursively thinking them. I would suggest that you distract yourself with things that fully engage you thinking to prevent this. This can be any flow experience or just doing things for others where you are not left to think of yourself. This is closely linked to mindfulness, which might well be helpful too for you. Second, you need to give credit to the small things that are terrific about you that you have taught yourself to ignore, minimize or otherwise overlook. Thus, try recoding these in a small note book. Your goal is to identify at least 3 such events each day. They need not be big huge things it might be as simple as "I made a really well cooked scallop for dinner" or "I smiled at someone without worrying about how 'horrible' I am". Record those small things. Third, after doing one and two for a bit things should be a less glum, now its time to challenge those thoughts of yours. This will require you to catch the things that you still think despite your attempts to not think them (intrusive thoughts) and your attempts to notice the small successes each day. Then challenge them, in simple terms as yourself "why do I believe that this true of myself and how can I test that against unbiased reality?" This is the heart of cognitive therapy but it is effective and you might have a therapist skilled in this coach you in it.

One of the barriers to your success with the above will be your own sense of learned helplessness, basically your inability to see an escape from your current pain. This is why a helpful and appropriately trained individual might well be a huge help in getting a kick-start to success in this process.

For what it may be worth to you, I know it is possible as I have seen it occur in others. There is nothing remarkable about them, but they were able to obtain success over a major life challenge. I would wager you can achieve this as well.