CLKD, "journaling", do you mean just writing out all your thoughts every day? I would be keen to do that if it helped stop the guilt. That's encouraging.
Yes, I'm afraid I do tend to give at home rather than overseas, apart from when I halped IAKA for a while (South Korean dogs charity, those poor dogs, it's awful).
We're not responsible for the Big Bad World no, but I still have my guilt with my own pets, and it's not just the 'final decision' thing because I know in my heart that was the right thing to do for them, it's also that I am obsessing that I don't feel I always did good enough for them all the time. It might be the hormones making everything seem 'large' and 'out of perspective'.
It's so bad I can't even look at dogs this last couple of weeks, nor horses - I used to work in a riding school as a youngster and looking back I think the horses were overworked, could I have done anything about it? No I don't suppose so, but that doesn't make me feel any better. I may just have to accept that I really am going crazy now and will watch out for the yellow van ....