I wish I was committed enough to keep a journal.
I always do it for about a week, then forget about it for months.
Also yeah, if you listen to depressing stuff all the time it's probably going to rub off on you, no matter how detached from the person/the person's situation you are.
Also also I tend to draw/come up with ideas for my comics late at night too. It's just something about being exhausted that makes me see things in a strange light.