Can someone please tell me what to do ?

This will be really long , but please bear with me . I live in very hard conditions . My so called father left me when i was only 2 years old . I only meet him in court , cause he refuses to pay for me , since my parents are divorced and i live with my so called mother . I don't hate that man . I don't waste my time thinking about that ************ . My mother on the other hand , lives with me but i can't really call her my mother , cause she isn't fit for the one . From the moment i know for myself , she was babying me . I tired to prove her that its bad , and that might harm my development . I am 15 years old guy right now , and she still does it . She always nags me about something , sometimes is the way i am holding spoon while eating , articles i read on internet , the way i put my socks on , my attitude and many more things she has no right to decide . You probably think that i am crazy for saying that she has no right as my mother but i will explain now . I live with my grandparents too . To sum it together , its : me , mother and my grandparents . They take all care of me , but i really mean it ALL . We live in one big house , i live with my grandparents on the 1 floor , and she is down there , i don't even know how to call it . She barely completed her 3 year high school , and barely gets a job at some tavern few miles away . It has gotten worse over the years . She married again for some nice guy , but he is so damn lazy , only he can be . As i said , marriage lasted 3 years , and well it still lasts , but this guy returned home since he couldn't take her . She didn't marry for better future of her only son , but simply because of that man's "cute blue eyes" . Its like she didn't even got out of puberty . Sometimes it looks like i am more mature than her . I get good grades , my gpa is around 4,1 , i don't smoke drink or do drunks , i don't go to parties and clubs , i don't go out at all , something that even my grandparents judge . I know how to handle money , and i save money , but i don't even know why . I afford my teeth prosthesis , glasses , and high school fees by myself from the money i saved up , and when i ask her is that the way a mother should act , she just says "Aleksandar , you know that mom doesn't have money . I mean WHAT THE **** ? Aleksandar is my name btw . The same thing happened when my school books were in question . My grandparents had to pay with their retirement , that can barely cover basic life expenses up . I am very understanding teen , and i never throw fits or anything . i understand that crisis caught up whole world , and i never begged for a new mobile phone or something like that . My grandparents are my only support in life , but they easily get upset over minor things , usually revolving about MY DEAREST MOMMY . I don't even know if this is a question , or the silent confession of my soul . I am very good with technology , especially computers , and with languages . English isn't my mutual language , but i had to write it this way , for you guys to tell me what to do . I am a loner , and i don't like to hang out . I prefer company of older people , since i find my pals to me little childish . I am very unmotivated to do anything in my life , but there is one thing i would like to do . I would love te become a digial nomad . I mean to leave all **** behind , and go globetrotting , and finally living this goddamn life . I am not planing this until my grandparents die , cause they don't deserve to be left by me . I own them an hell of things . And to tell you the truth , my mother is the reason my father left me . He just couldn't handle her anymore , and left me with the devil . Now since she works at tavern , i fear that she might start drinking , and "falls to my back" . I told her to find some rich husband , since she won't have retirement with education and work like that . But no , she lives for today . Please tell me what to do , cause i might run out on the street naked and scream that i am a messenger of god . Sounds nasty , but really , it's come to that . Please help me guys , this has gone too far for me to handle . Thanks in advance and happy new 2012 !