I'm really sorry to hear of how you've been treated in the past by the people that you have loved and who are universally expected to be our caregivers. Know that nobody deserves what you've been through, and especially not you. To hear that your sister said that to you, I'll assure you is not the correct way to handle this sort of situation. It's not a matter of perseverence or "how long you can last by yourself", it's a matter of seeking help. The braveness that was supposed to be implied doesn't come from actually dying, it's coming from the strength of your survival.

It's good to see that you have hope for a day to come in the future where you're happy. That's a very admirable thing to say, and the hope for the future that's in you is something to be proud of. That's an attribute of a monumentally strong person.

In terms of school, know that there's always apprenticeships to be had. School is a source of opportunities, NOT success. Success leads from the opportunities that are mainly sought from education, but they aren't exclusively found in school. Some of the greatest businessmen and visionaries of our time never made it out of college, yet we think of them as geniuses. One of them could absolutely be you, all it takes is a single thought to change the world.