Cope. And a stupid one at that. I would write a long thing on why you shouldn't do that and how you're just being a satanic edgelord but CBA tbh so I'll sum it up in a few shorter paragraphs...
Orphanage won't accept you without death certificates.
Adoption homes are rough and have no space; they wouldn't accept a runaway with a home to go back to. You have to be at least 17 to leave home without parental permission. Also you're 5'2. You'd get bullied in social services...
You will not get enough money to afford accomodation at you're age. That's low IQ. You won't even have finished education so good luck at getting a job. And all the other necessary living expenses you most likely overlook.
Basically it's a stupid idea as you'll be back within 72 hours without your parents and you wouldn't make it in the world... Yet at least.
Just stay at home. You are probably unaware of how easy it is for you, despite your parents fighting, not understanding you, not being there etc. It's still free accomodation and food and school is bad but you've only got a short time left (depending on where you live)
I don't mean to come off as rude but you're likely just looking for attention, from us or in real life, and I doubt you would seriously cut all ties, even moreso without being returned. This is a retarded fantasy as the world is nothing like you believe. You can't simply just "leave" and make a successful living. You're not Chad and this isn't the dating market. You have to work hard to get what you want tangibly. Minimum wage is nowhere nearly enough to sustain you, especially as you're so young.
Don't.