Why is when someone has problems , no one cares until that person kills themselves? i feel that way.?

all my life i felt low , i never felt good at anything , and it kills me because people dont keep it to themselves to make a person feel they arent nothing. I hate my life it sickens me , i just want to go awa sometimes , i hate existing everyday because it hurts so much that living isnt worth it sometimes. I've had people tell me things that disgust me , when i was 11 , i remember being out with my mom to visit my uncle and he was talking about how much weight i'd gained , so when we got home my mother says " you embaressed me." when i was 15 my a friend of mine " told me i was the weaker part of the species." A cousin told me " who would ever want to be like you?" a clmate told me when discussing girls that we thought look hot , which every guy has a dreamgirl but wont necessarily marry that gir but he says " you're ugly how can you be picky?" i once told a friend that i wanted to be something great before i died ,i dont want to die a normal person so he says " thats most likely what will happen." but he has high expetations of himself. How can I continue living trying to smile when someone destroys my world everyday? i've been depressed since 2008 and it only gets worst.