For a pessimist, I'm pretty optimistic.

You can't constantly whine. You can't always give up and think that somebody else will help you. No one will. We're selfish, we only think about our own happiness. What could make others happy doesn't matter as long as our own happiness isn't involved. You can't constantly act like an attention seeker just for people to notice you're alive. Trust me, people who make everything to be noticed are unbearable. Stop one moment and think about everything you want. Is it really impossible? What is stopping you? Nothing, no one is stopping you. You can't let anybody tell you what to do or how to feel. What your life is gonna be like is up to you and only you. It's okay to cry, we all do. But then, you have to use that pain, use that anger that's eating you alive. You have two choices: you either let it kill you or you can move your ass and do something about it. People won't always be there to tell you that you're loved, that you're worth it and that they believe in you. You have to start acting alone. Think about what you want. Only you can make a change. And you can make it now.
Sure it won't be easy but you have to fight for what you want. You failed? Try harder. Someone's telling you to shut up? Scream louder. Stand for what you believe in. No one is able to take it from you. People will always make you feel like shit and you know what? They may be right. As long as you don't believe in you, in your abilities, you will be a failure. Take a step, go further. Believe in what you are. Believe in the person you aim to be. Once you're able to do that, there will be no better version of you. Smile.