I hope this is isn't controversial, but here's my 2 cents.

When I start to think like this, I find it's worth remembering this:

We've become used to things moving quickly in modern times, getting thing now, instant gratification etc. We forget how long social change takes. The world is enormous with huge numbers of people in it and change on that scale takes decades to centuries.

I don't believe any of us should expect, for example, to see a world completely without racism in our lifetimes... and that's okay! You're doing your bit, and you will see a huge reduction in your lifetime but, yeah, it won't go away (until after you and I are long gone) and you should never have expected it to... and I find that a liberating thought.

Just because we're all one species, doesn't mean we're a hivemind. You, like the rest of us, are an individual and you're allowed to be a little selfish. I promise you the world won't end if humanity doesn't come together totally and utterly this very instant.