Yes, a couple of years ago. The story bears close resemblance to yours. Layers of stress at work and in personal life. No drugs were involved. I'm still recovering emotionally, mentally and financially. It was life-threatening.

I now dread taking on resposibilities or even reaching out to people I lost contact with, fearing a relapse of sorts. Therapy wasn't particularly useful, maybe because I got myself to go after I was already snapping out of it. My guess is that it sort of "just happens" to some people under the "right" circumstances.