I need advice! please please help!?

The past few years it has been very very hard on me. I've been moved around, and sabotaged by families. I am in foster care, and have 11 siblings who live in my town; and who are older now, but are drug addicts and criminals, drug dealers and so on. Anyway, I lost my mum on Christmas Day. I lost my cousin on Christmas Eve. The last foster home I was in I witnessed suicide with other kids, and the foster parent was never even around. The one before that; I caught the boyfriend cheating on the foster mom ( which they have been together for 8 years ) & that devastated me. The home before that one; I was sabotaged ( long long story ) ; I basically got told I was used for the money; and got told to leave 2 in the morning with no where to go. Anyway, I haven't been so great in school; with all the drama I've delt with. There was a family I lived with for 12 years; it didn't work out there though...too much yelling, and fighting, and arguing. I got molested in that home by a babysitter, and they didn't believe me. I was left to cry every night, and I just finally ran away. Anyway the family I lived with for 12 years; I've been very missing a family..Considering I live with my boyfriend at the moment. He lives with his mom, and brother and his brothers girlfriend is always there too....and she pisses me off. They say I'm a ***** because I act too mature, and yadda yadda. Anyway...they dont have much money so I don't eat their food, and I am on welfare, and have my own little studio right now in the bad part of town...so I stay at my boyfriends and just buy little snacks to munch on. I have been on the streets before, trying to just not be a burden on anybody. But my boyfriends mother said i was able to sleep here. Anyway....it's not the best place to stay, I don't get along with my boyfriends brothers girlfriend because she is very immature and throws parties that I've been trying to control. My boyfriends mother isn't around much, and when she is she just drinks and sits in her room ( because shes been through alot too ) I'm not a bad kid, I try and I try. I clean up around here, and try and pitch in as much as I can. I'm just sick and tired without being without any guidence. I feel I never lived a childhood, and my life is unfair. It's hard living on your own at age 17, and I missed 1 semester of school; and I feel I'm a failure. I feel I cannot cope anymore, and deal with all this nonsense. My boyfriend helps me out a lot. He works full time though and he has bills to pay and his car isurence, and his mothers rent, and his own food. So he just tries as well. Anyway, I don't know what to do, I can't really describe my life the best way possible, I just feel I've lost everybody along the road, but the 12 year foster home I stayed with said I can move back anytime...but I went their for christmas and the yelling and aruging and constant bickering just brought me back to the old days, were it frusterates me, because i'm not that type of person. I just want somebody, somebody to be there for me. I told the 12 year foster home I would move back, but now I don't feel like it, and I feel.......so lost! i don't know what to do! I don't want to hurt them...yet theyre very strict and argumental people..which I can't take..I've told them to get conselling..but they wont. theyre very stubborn people. Anyway.......I dont know please help?