Anti-depressants aren't like a "happy pill". It's not like soma from a Brave New World.
Of course you can change yourself, all problems are within you, they are created by your optimization function. Apocalypse is not a problem unless you don't want it to happen. Without people who don't make themself content with the state of things right now it's not a nice place to be. But without people who are not content and are trying to fix it it's not getting better.
Just to be too verbose because of sensitive topic: it may be you, it may be chemical imbalance, I'm not saying it's a happy pill and long story short if you haven't experienced happiness in a long time go see a doctor yada yada.
You can be happy during apocalypse when you are making progress towards ending it, you can not like things and accept it. I'm just making a case for unhappiness being the sane reaction in specific contexts.
It's really hard to have a meaningful discussion about this topic without being seen as a murderer while providing a decent information density. Even on HN.
If you weren't susceptible to depression these spirals wouldn't take hold, you might just say, "huh, now that I've learned more, I realize this is a harder problem than I first thought" and you just carry on.
Imagine a kid drowning in front of you (that somewhat happens but on the other side of the world so you can't see directly). You can be unhappy about it, but that's within you. If you don't care about the kid you have no reason to be upset.
Most probably would agree that maybe doing something to yourself to make you less upset about the kid drowning is not optimal. Reality is somewhere between this and somebody living a perfect life and wanting to kill himself.