Hi THAT Girl,
Welcome to our friendly online community. We think it's great that you've reached out here to ask these important questions - it can take courage to do so, so thank you. There's no harm in expressing how you're feeling. It's common for people to feel that their mental health is not 'bad enough' to open up to others about it or seek help, but the truth is that it's never too early to seek support, and it's a good way to prevent things from becoming worse.
We're really sorry to hear that you've been feeling that you hate yourself, this sounds really distressing and something that is definitely worth asking for some help with. It sounds like it would be a good idea to tell your parents - you might be interested in our page that offers some tips on how to bring up the subject - “Talk about it"” - https://www.beyondblue.org.au/get-support/have-the-conversation/talk-about-it
You may also feel that it would be helpful to chat this over with a counsellor, so please know that you are always welcome to get in touch with Kids Help Line.
They are a confidential and anonymous, telephone and online counselling service specifically for young people aged 25 and under. You can chat with their friendly counsellors on a webchat if you find that most comfortable.
It's also often a good idea to get in touch with your school counsellor if you have one.
Thanks again for reaching out here, and please feel free to let us know how you're going anytime here on your thread.