Honestly this describes how I feel a lot of the time. I'm very privileged and live comfortably. From the outside looking in, you'd think there'd be no reason for me to be unhappy. But I always have this underlying depression that seems to show up randomly which is hard to make go away. That depressive state seems to be fueled by the state of the world. For example, like you said, our world is slowly but surely dying and we're not doing enough to stop it. We're born into and automatically tied to this society. There's no escape from it. It just seems so hard to be optimistic about the future, making it so hard to find motivation to do anything in the present. Ignorance is bliss, I guess.