How Can Severe Depression Be Treated?

My name is Gaia. It s been 2 years since i first thought that i had depression and i ve been self-harming for years now aswell. I m 15 and I m in my last year of school and all the time i feel like my mind is buzzing full of negative thoughts and i constantly feel as though i m falling apart. I was wondering if you know whether it s possible to get professional help without my parents knowing? I understand that it s not likely, and that in most cases if you re in risk of harm to yourself or another someone has to let your parent or guardian know, but i ve been researching for the past hour now and all i want to know is if there is anyway to work around it and just find a system where no one but me has to know about it? I can t afford this website though so just ignore everything i just said. I m going to go and kill msyelf, thank you for your time