What you're feeling is understandable and remarkably common... you shouldn't feel that you're alone in feeling these things.
How old are you? The world can be a very confusing, scary, and saddening place for young people these days... especially if they are in adolescence, if they have a strained relationship with their parents, and they have been given incomplete (and often conflicting) images of what life is all about.
Children can be cruel, the public school system can be nasty and unforgiving, parents can be impatient and stressed and unhelpful, and strangers all around you can very easily bring their own miseries into the way they treat you to make it all feel even worse.
I understand how hard it is... I have felt this way myself at points in my life... but I am doing better now.
So there are several things I can offer to you in the hopes that they may provide you some comfort:
1. Trust yourself, and your feelings, and your beliefs, and your questions. If you feel that the things you've been told do not make sense to you right now, then that is okay... re-think them... find your own answers. The only "truth" you need worry about is the truth that feels right to you. If you feel the purpose for you being here is to change the world, try to to do it... or if you feel the whole purpose is to just find something you enjoy, then just pursue that... or if you feel you can only find comfort and meaning somewhere far away in the stars, then dream about it, and believe in it. It's okay to feel what feels right.
2. Understand that you are, and always will be, a companion to yourself. You are never truly alone as long as you still care about yourself. Your thoughts and feelings never go unheard as long as you are listening.
3. Realize that things will change. It is hard to believe now, I know, but things will get better. When you are older, answers will start to come to you. Love WILL happen for you... people will treat you with more respect (it's unfair, but it's true)... your peers will become strong enough to express their true emotions... you will find you have more in common with more people than you ever thought possible. Nobody ever really believes this one until it happens... but it will.
4. Know that you have the power to make your life into almost anything you could want. It may not happen right away, and life as an adolescent under the care of difficult parents can sometimes make it very hard to choose your own path... but you will have the opportunity to do amazing things. Start thinking about this now... plan what you want... what you need. You are good enough to accomplish anything. This pain you're feeling will become a gift of will-power and motivation and adrenaline. You can get there.
5. The world is bigger than you think. There are a lot of people, a lot of places, and a lot of things that you could maybe never even imagine.
6. Don't commit suicide. I was tempted to committed suicide once... my fiancee almost committed suicide once... if either one of us had done that, we would have never found each other. Take chances, feel alive, do something you've always been scared to do. The pain you are feeling is real, and you are a hero for facing it and confronting it, and attempting to understand it. Do not stop being that hero. I am proud of you.