I'm not sure how your life is but I'm sure there's somebody who cares about you even if you don't realize it. I'm unaware of your family life but I'll just assume that your parents do actually care. They may not be showing it or not showing it in the right way but I think deep down every parent cares for their child. Some times we have a hard time noticing that though when we're busy looking at all the awful things in our lives. We all go through phases where we dislike our life but that's the time when you need to try to look on the bright side. Try to find a silver lining because I'm sure there is one even if you're having a hard time finding it.
Don't you have friends? If you do then I'm sure if they're true friends they try to be there as much as they can. I know friends aren't always there because after all, we all do have our own problems. You need to learn to lean on people though. It doesn't make you weak to say you need help. It makes you strong because you're able to admit it.
Your ex is your ex for a reason. In simple terms, it's called break up because it's broken. I don't know what happened between you two but obviously something just wasn't working. You can't hold back on your happiness just because one person leaves. So many people will come and go from your life but you can't let that hold you in a rut. If she was meant to be in your life, she would be. Some people just come into our life for a short period of time to help us grow as a person, some people just aren't meant to stay. If you can't work things out with your ex, which I'll assume you can't because its been so long, you need to move on. It's not easy but it is possible. I highly doubt she's stopping her life because you two aren't together, why should you do that for her?
We all just want to be loved, in many ways. Just because you given your emotions to others and they haven't been returned the same doesn't mean it's impossible to find someone who will share mutual feelings. It's all about time. Time heals all and it also brings what we need to us. The important thing is to not give up, you can't lose hope. Life is rough but we all have to push through at times. You can't expect things to always be easy, nobody gets the easy road.
Honestly, I suggest you start talking to a therapist. We all need someone to talk to at some point and it does really help to get things out and to have another person's insight. Your life is worth living even if you can't see that right now. Things change every day, but the only way you'll be able to see this change is if you don't give up. Good luck.