Why is this life unjust?

Hi, I have very severe problem with accepting myself. I had a good character. I treated all people equally, i understood their views and always helped them (everyone i came across) out. I did only good. In other words, I didnt know what was the bad. I studied hard and entered the university. Here I behaved the same towards people. But here I learned envy, jealousy. I wasnt jealous but the other people were jealous of me. I dont know why. I didnt pay a single attention to their envy but wanted to help them, I wanted to make people cheerful, forget their malice and they did. But after years in my 3rd year of university I began to hate. i dont know why i hate and i hate to whom. I began hate the life itself. i began to hate the genetics. I began to hate the God. I began to hate the injustice. I was optimist and now my character is being reversed by the society by the life itself to the pessimist. After every good thing i did to everybody, i came across with the bad things did to me. I read many psychological books in order to understand the people and i did almost. after that i fell in love with a girl but didnt want her to know it because she was 1,85 cm while i am 1,82. I promised myself that the opinion of others dont matter to me. But i avoided. I didnt know why then. Then i understand, even if the girl do accept me, i dont accept myself. I am 19 year old. And this impact made me only fall. I began hating people. Even i began being jealous of them. Sometimes i remember the attitudes of the people previously to me and i hate myself being jealous of innocents. I began to hide my face when i am jealous. i cursed myself. Now i think that if i die the "life" will be end. at least for me but actual life is going on. does it matter for me if i am dead. After my fall i began to look the life in different way. I saw everything sometimes i observe people's face and admitted that our pains are nothing compared to death. I began to think why we die. we study for some 15 or more years not to understand the life, not the other people, but understand ourselves then we do create our life but then we die and get the rid of our hands from our lifes and die. I began to hate the religions too. it is nothing but consolatory to the people/ I know that there is nothing but our graves, we go back where we came to the earth. I dont know sometimes i want to lock myself in the room. when people see me they say you are so confident you are so determined you manage to do this that.but they dont see my inner feelings. Why am i like this? will i be okay? sometimes i say i want to be a mad and dont understand anything and live just live. i want to cut my past but i cant.Pls tell me what to do. sorry for my english and i wrote this all in one start and even there are more words left inside me.what do you suggest to me?