The definition of a Major Depression

So clinical depression, if I understand it, comes on without any reason. Right? So if I am unemployed for 3 years and have a 3-year-old and no money, that is normal depression? I mean, you would have to be a zombie NOT TO be depressed.
I am asking myself to try to understand my diagnosis.

I guess I always assumed major depression was one that doesn't go away and is always there, no matter what. All I know is every time I do a self-test, the website test gets more agitated about my results than I do and advises me to seek help asap, ha.

What diagnosis do you in fact have? Clinical Depression?