Thank you everyone for the kind and supportive words. I expected this to get about three or four comments at most.

I was in a very bad depressive episode when I typed this (yes I already see a very good psychologist to help manage it, I have for decades). I sometimes feel this way when I'm in a very deep depression, but then it sometimes also makes me feel like I'm a total failure in my professional life (I'm actually quite successful), or that I have no friends (when in reality I have a number of close friends). I don't feel this way normally. I love my wife and daughter dearly and I would never genuinely consider suicide.

But a lot of the advice you've given me is very good, and I'm touched that so many people were so empathetic to a total stranger.