Why the world is unfair?

In class there one girl. She doesn’t do anything for classes but manage to get good grades. For example, for one class I did last project bad but all other ones were good. But I got +B, and she got -A. I talked with teacher and she changed my grade. But she said she didn’t do other two last assignments. And all her other works wasn’t good at all.
She talks with everyone, even with guy I like. She has big birth mark on face. But she managed to be liked by everyone, but not me. Why the world is so unfair?
And when I say that, I don’t have boyfriend or friends, people say “just try harder”. But I constantly try harder, and my every mistake harshly punished, like with that last assignment that made me got +B, while others don’t care about anything and don’t try hard and loved by others.
And I don’t think I’m uglier, but still don’t get it. When I try to talk with people they try to get away or look a little bit scared😩😭 especially guys.
And she dates other guy, but still talks with the guy I like. While I got punished cause I slept with other guy and by coincidence my friend started talking about it in class and the guy I been in good terms started distancing. I got punished but I didn’t even date him😭😩 while that girl getting attention of guy I like even if she has boyfriend.
Why I always get punished for minor things. While other living their best life
Why the world is unfair?
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