As Lectorog said, this is a normal part of growing up.
However, you're missing a few points. By thermodynamics and irreversible entropy, the universe will eventually reach a state wherein in no new reactions can take place. This means that, no matter what you do in life, however spectacular it may be. Everything will end, the human race will die, and that trite "a smile can change the world" saying will look rather silly. You are not even a grain of sand on a beach, you're a quark in a star, nearly every one of your properties determined by location and random chance.
Tl;dr: Entropy makes your life about as hopeful as a kitten with metastasized brain cancer.
So, what does this mean for you? Not a damn thing.
There are beautiful things to see, puppies to hug, cat videos to watch, things to learn, strange dishes to eat, cool games to play, etc, etc. None of this particularly cares whether you are happy or not. It's just there.
Life isn't cruel and shitty, it just doesn't care. Snow is not cruel because it falls, it isn't happy, it isn't sad, it isn't anything, it's just snow. Understand that life doesn't care about you, and you're a giant step forward in being happy. If you can understand that life isn't personally being mean to you, then you can start to do a lot of things. When it rained, our greatfathers didn't bemoan the world for being cruel, they hid in caves. Actually, I don't know if all of our ancestors were that stoic, some of them might have spent their lives wailing at the raining sky, and subsequently ended their lives like stereotypical turkey's, but I really don't know about that.
Life is hard, life is uncaring, life spends a great deal of time making you want to curl up in a ball and die, however, it is also the only chance for fun that you will literally ever have. (For certain, anyway. If you've got a green card for one of the theological paradises, good for you.)
Everybody copes in their own way. For me, it's sarcasm. For others, it's faith, or making other people's lives less miserable, or making a ton of money, or any of the bazillion mechanisms that justifies existence.
Anyway, short version: Life isn't out to get you, it just doesn't care whether it accidentally crushes you. Everybody feels like this occasionally, and we all cope differently. If there's a way for you to laugh, take it. Dark laughter is better than no laughter. Life is pain, to quote an excellent movie line, but it's also pleasure. It is the source of both.