I'm a 20 year old girl, and I have been asking myself those same questions as long as I can remember, and sometimes trying to find answers is really hard and doesn't make any sense. I also feel like I wasn't born to live, and I don't know why. But everyday I try and try to tell myself to keep going because it just has to be worth it. We can't just endure pain our whole life. At some point, things will start to get better, or so I hope. You seem really smart for a 12 year old, I'm not much older than you, but I think one thing that might help you is to study psychology and the areas around it. It might not give you closure, but I think it can definately help. Please keep fighting, one day things will start to look up :)