ohdear, I don't feel like that much now but I have done in the past and in fact nearly succeeded in taking my life years ago aged 21. I'm very glad now I didn't succeed. Whatever is going on in your life it's better to be alive than dead. And as the daughter of a father who killed himself (when I was 19, partly the reason for my own depression during those years) I have to say you can't as a parent really do this just simply because of the devastation you'd leave behind.
Having said all that, I totally sympathise with how you are feeling. I know the emotions very well and for all the years since my worst period of time I fight against that kind of heavy dark depression coming back. I've taken medication in the past which took the edge off things but didn't really help massively. BUT I have been seeing a psychotherapist for about 6 years now (on the NHS so that shows what a state I was in for them to fork out for that ) and it's been the very best thing I've ever done. It's helped me put things into perspective and understand myself, my past, the way I deal with things now.
I think that if you have a tendency to depression, when things go wrong in your life (and being in debt is a horrible state to be in, I've been there many times and still am though am sort of 'on top' of it now) it's hard to deal with them in the way non-depressed people often can.
Does your partner know you feel like this? Is he able to help at all? What about other family members? (You may have answered these questions earlier, haven't had time to read the whole thread, just your contributions).
If you EVER want to CAT me, please do, I have lots of experience of this both in relation to me, my father and my brother.
Wishing you much love and support xxx