What am I doing wrong?

I have always told myself that life will get better, that everything is just a matter of time. Years have passed, but I just feel like nothing gets better. At the end of the day I’m only 16 years old and I feel like when I can’t deal with my problems now, how can I when I’m older? To be honest, I don’t even know what I’m doing wrong with my life. I always try to be friendly and happy, and as I’ve heard most people think I live I pretty normal and content lifestyle. But why is it that every night I cry myself to sleep? Why is it that I always feel left out? Why is it that I will never be good enough? Why isn’t there something worth living for? I’m alright with not having many friends, to be honest I only really have two friends, and most of the time I feel like they don’t even want me around. But what I don’t get is why mu parents dislike me. I try to be nice, I do what I am told and I write good grades. What more can I do? Is it so difficult for them to show me just the slightest bit of love, the slightest bit of appreciation? I feel like especially my mother tends to feel hatred towards me. Instead it always feels like she’d rather have my cousin as her daughter. And I’m not gonna lie this makes me jealous, my cousin is just a year older than me; she’s failing school, she is sort of a rebel towards her mother, she smokes and vapes and so on, basically everything that would send my mom into a coma. But somehow my mom doesn’t bother, she always gives her money, buys her presents and invites her to trips. My mother has never in my life bought me a present or invited me to a trip. She didn’t even bother to raise me up. Maybe that’s why I’m such a mess, not being able to love, not being able to have a friend group and not having any talent. It feels like I’m just breathing up someone else’s air. I feel so incredibly pathetic when I know that people have real problems out there and I here sobbing over my problems wanting to die when there are people out there fighting for there life’s. but it’s just so difficult to live a life when there’s no one caring for you. And the most difficult part is having no one to talk to, I have kept silent for so long that everyone expects me to be this average happy person.