It's a matter of perspective. I think there has never been a paradise for humans, our nature is such that we experience both good and bad... in fact I would guess that's just what life is. Life is pain and pleasure, suffering and enjoyment, up and down. I've had periods of time where I felt as you do, but right now I see a lot of good, despite the intensity of these times and despite the amount of pain and suffering there is.
One technique I use to remain happier is that I don't read the news stories every day (or much at all). At first I felt like maybe I was just hiding my head in the sand, but then I realized, reading about or hearing someone doomsay about the terrible things happening doesn't do me any good. It doesn't help to fix these problems to continually think about them and expose myself to that information. The best thing I can do for the world is to be the best version of myself I can be and try to bring some light into my own life and the lives of the people I know and interact with. Then maybe they'll be more likely to do the same, and so on. When I encounter darkness in my life, I deal with it head-on. But without the daily exposure to all the bad things happening all over the world, I am able to see a lot more good in my immediate world, the place I live and the people I know and meet. Yeah, terrible things happen to people constantly when you look at a population of millions, or hundreds of millions, or 7 billion, but there is also a tremendous amount of good happening in those same populations. The news just doesn't cover that kind of stuff, the basic kindnesses that people show each other every day, the feeling of hiking to the top of a mountain and viewing a beautiful sunset, the feeling of genuine human connection or love, and so on. I think part of the problem is an overexposure of information, mostly negative.