"I'm ulgy, fat and stupid and nobody loves me :(((
"He shouldn't treat me like that!! I wish him suffering! Grrrr!! I hope he burns in hell!!!
"Oh my God, life is so unfair!! It's horrible and I can't stand it!!
Of course it's unfair, it's life. Shut the fuck up, stop whining and start using your brain so you be happy (lol, I'm being a little bit aggressive here, let's relax ;))
Stop creating fantasy worlds where everything should be the way you want it to be. Accept reality as it is. Sure, try to change the things that you don't like about it (if you feel like it), but accept it unconditionally. There's no single evidence that life should be other than it is. Life doesn't give a fuck about you and your goals nor about what you consider appropriate or inappropriate, good or bad.
Stop telling yourself that others must behave the way you want them to. You are not a god; you're just an insignificant primate. You don't rule the world. Your moral code is not universal; it's just a subjective view on ethics and there is no single evidence that yours is the only "correct" one. Sure, stay away from individuals who treat you badly, but don't be so stupid that you let yourself think, feel or behave in a self-defeating way: don't get yourself angry, resentful, depressed, anxious, guiltful or shameful. Please... do yourself a favour and don't act in such a masochistinc way. Don't make up your own enemies. There's no single evidence that people should treat you well (or bad), for there's no single evidence that people SHOULD, MUST or HAVE TO. In the other hand, there's a lot of evidences that predict that people have physical freedom and will sometimes behave stupidly and in an antisocial way. We all would like people to always treat each other kindly and justly, and we strive for a future world where that happens, but demanding it from reality right now is nonsense, because you are demanding somethig that doesn't exist. Accept people unconditionally. Condemn what they do but never condemn their being. As much as you wish, you can't totally rate anybody; it's logically and empirically impossible. Don't demand perfection from others, they are fallible human beings and they're about as fucked up as you are. They will always do wrong things, but that doesn't make them wrong persons, just persons who acted wrongly.
Stop thinking that you are a shit, a waste. Obviously, you are not. You are a living organism who wants to get pleasure and avoid pain, just like any other living thing. Also, as I've said, you can't rate yourself or anybody; it's impossible. So choose to accept yourself, no matter what; no conditions. Just choose to accept yourself because of being a living organism and wanting to be happy. Also, stop thinking you are special, if so. You're just a primate, like everyone else, and almost nobody in the world (and universe) gives a single shit about you. You will eventually die and nobody will care. Do you care for this man who died 1,037 years ago, whose name nobody knows? Obviously not. Do you care for Napoleon? Sure, you do care, but he is dead, so he doesn't feel the oh!-so-great-and-noble pleasure of being remembered, and so won't you.
Stop giving much of a crap about what other people think of you. Rejection it's not the end of the world. Actually, rejection leaves you intact; if other people reject you, you don't have to reject yourself; you always can choose to accept yourself unconditionally. What's going to happen to you if people reject you? Almost nothing. So, who really cares? Words don't hurt, punches and kicks do.
You feel you are ugly? fat? too skinny? stupid? Ok... let's suppose that you not only feel that way but you are that way. So you are stupid, so what? Do you need to be intelligent in order to be happy? That's bullshit. There's a lot of feeble-minded people who are really happy. Who cares about intelligence?! Actually, you can't prove that being intelligent is better than being stupid. But, even supposing, as almost all people do, that being intelligent is better than being stupid, you do NOT need to be intelligent in order to be happy. Being happy is the only thing that I (and, i think, sane people) consider really important. The same if you are fat, small, ugly, etc etc. The bullshit that media and society tells people that you have to have the approval (and even envy) of other people in other to be happy is pure bullshit, as I said. You do NOT need approval from other people. You do not need success. You do not need anything except water and food in order to be happy.
Yes. You don't need almost anything. You think you have to reach a lot of goals and accomplish some other trivialities in order to have a great life, but that's nonsense. Let's be honest, as always: If you're not happy it's probably because you're thinking in an stupid way. No, it's not because of the unfortunate things that have happened to you that have made you unhappy. That's bullshit. Nothing and nobody except YOU can make you unhappy. Stop whining. If you are not happy it's because you're thinking in a self-defeating way. Yes. All this time you were thinking that you needed things that you actually didn't need. Sure, you wanted them and you still want them, that's fine, that's preference (opposite to demand), but you didn't NEED them. You didn't accept reality unconditionally but conditionally, and so you were happy sometimes, when you got what you thought you needed, but you got way back to shithood when you didn't get it.
You can be happy for the rest of your life. You just have to start using your brain. Accept yourself, others and life unconditionally. Acknowledge that you don't need almost anything in life in order to do great things for you and other people; in order to be happy. Acknowledge that nothing is horrible in life, even when you suffer so much (suffering is a necessary part of life, so accept it). Acknowledge that most of your problems would be silly trivial things for non-occidental people. Accept that you will eventually die. Acknowledge that nothing MUST be, and that wathever happened, happened; deal with it. Refuse to make yourself crazy.