Hello again, sorry I'm having internet problems today.
I went through something similar. I had a rotten childhood - my mother was a bullying drunk. I learned to ignore my own needs, she trained me very well and so I picked men who would be emotionally draining to me as well. Deep down I thought fixing other people was my role in life. I ended up dumped with two children and a big pile of debt. I worked like a slave to get out of debt and to support my children, and eventually I could feel, as you put it, my facade cracking. I knew that the time was soon coming when I might no longer be able to cope, and then what would happen to my children? So I went into therapy. As rev said, a psychiatrist is different from a counsellor. A counsellor will listen to you and be sympathetic, but a psychiatrist will follow your lines of thought and help you to uncover the truth underneath everything. You do the work, but the psychiatrist guides you through your own subconscious. Then you find out what motivates your choices so you can make healthier ones in future. And you find out what things in your past are unresolved sadnesses for you, so that you can address them. Sometimes you find that you've felt sad for years over something but that you've never felt that anyone has every really heard you, perhaps you haven't even heard yourself properly. Once these issues come to light and your feelings have been expressed, it's like the burden is lifted off you.
You can't really do this on your own, once it gets to the stage you describe - try as you might it is very difficult to uncover your subconscious wounds on your own.
Another thing I've noticed is that only people who are very good copers normally suffer from this kind of depression. People who are bad copers blow a fuse at the slightest thing, and get all their issues off their chest at the time. Good copers go on for years, smiling through their tears, being strong, and then suddenly one day they just can't do it any more, they have reached their limit. When that happens it can feel bewildering, because you're so used to being a capable sort.
I was lucky in that within a few months of starting my therapy I met my wonderful husband, and he loved me through a few tears, I can tell you. It was only when I found myself in that safe place that I was able to fully express all my sadnesses from the past and find healing inside myself. There were days when I couldn't get out of bed, couldn't speak. Nights when I just cried for hours. And my life at that time was the best it had ever been. My subconscious obviously thought that it was safe to come out so there is a point to it all. And you can get better.
I never fall down with depression any more. Rotten things still happen to me sometimes, like they do to everyone, but I don't make dreadful choices any more that guarantee unhappiness. And all the old sadnesses don't come back and haunt me any more. Psychotherapy works.