My parents hate me but I don't know why?
They probably don't hate you, though it's not something you can rule out altogether.
It may have nothing to do with you. It may just be the fact that you exist and they blame you for their lives taking a different trajectory since you were born. This is bullshit, but it's how some people think and feel.
The best thing to do is ask them. Mom, Dad, I feel like you hate me and I don't know why. Do you? Why?
It might just be that they are disappointed with some of your choices. They might be afraid for you and trying to protect you. They might hate you.
If they do hate you, do what you can to move out.
If they don't, listen to them carefully. Try to take everything they say from the standpoint of “They love me, and they are acting this way because of that. Let's look at why.”
For instance, some people think rewards and punishments are necessary to direct a child's actions to be a good person. You might see them as arbitrarily taking things away from you or making your life difficult. If you open up a conversation, and commit to an open dialogue and understanding the why, you might come to see things a different way.
Please open up the conversation. It seems crazy scary (What if they do say they hate you just because you were born?), but what's the worst that can happen (They say they hate you because you were born.) At least you'll know where you stand.
And then you can ask, “Okay, here we are, I'm born, what can we do to really make each other's lives great together?” Inside of an inquiry like that, you can create some miracles.
Try it. I think you'll be surprised by what shows up.