Depression isn’t fair.
Mental illness isn’t fair.
We shouldn’t require happiness of ourselves. Depression is not about emotions, not at its core anyway. Depression is an illness, depression screws with brain chemistry.
It’s like if you had a glass of wine, and suddenly someone replaced it with a glass of cod liver oil. No matter how much we “should be happy” about getting wine, we’re not getting wine. We’re getting cod liver oil, and there’s no real way to choke down the stuff and think it’s wine (at least, I don’t think so, I’ve never had cod liver oil ><).
I see this in myself and in some of my compatriots at times, we’re mad at ourselves for not being happy in a good situation.