I think I need help.

Okay i am 15 years of age and I’m turning 16 soon.
i just want to express my feelings and why i feel like i really should not be here anymore.
i guess i just don’t feel like life is worth living.. or rather i am not worth living.
i wont give you ALL the gory details but long story short: my parents split when i was 8 or 9 months old. i lived with my father till i was 5 and i never saw him again. my father died when i was 9 and ever since i can remember my mother has been jumping from man to man-usually using them.. sometimes more than one man at a time. she is really unapproachable and i guess not the brightest crayon in the box. but she has been married now for the past 3- 4 years- unfaithfully.
i have “friends” if i may who ive been with for a long time – so a 2 years and a bit- only to find out that they constantly lie, back-stab and spread rumors about me. i know i can be freakishly weird sometimes but i never thought id deserve people so close to me do so much damage. i do whatever i can for anybody whether they have hurt me 50 times or don’t bother talking to me at all unless they need something. even if it means putting myself in danger or sacrificing allot of me or my time or resources etc. and it seems i am never appreciated or acknowledged. and when i am its because they have to or they just love to suck up. i don’t think i have anything physically wrong with me to be teased etc and i am usually polite and helpful and courteous and all the rest of it. i don’t really have a say in anything. i mean i used to but not anymore. i am an only child- but i have 5 ‘brothers’ and 2 ‘sisters’ all illegitimate or step. none of them really give me time of day except for my step sister when she needs or wants something. then i become the greatest thing ever given to mankind. but at any other time i am constantly put down. then i become the scum of the house. she also, in my mothers absence tried to be my mother. but its not her place. and she has no experience. see i have a boyfriend.. and i tell him everything that goes on.and i am so grateful for him simply because he treats me so well and i think without him i wouldn’t be seeking any form of help etc. i know my strengths eg i love to write poetry and stories etc.. and i used to aspire to be a lawyer but that went out the window a while back. i know i have i high level of general knowledge but that doesn’t help much here does it. i went to the doctor for a check up and he said i was stressed out and depressed and whatever doctors usually say but the happy pills never helped me. i act happy allot of the time because i don’t really want anybody to worry because then if it gets to my family ill be in bigger trouble and that wont help my state. i don’t think. anyway i just want some guidance or help here? because i honestly do not want to be here anymore.