Am i wrong to think this?!? i need help!?

ok so my best friend is kinda a b**** and she has used me ever sence we became friends the first guy i ever liked in 5th grade liked me and she didnt even know the guy then she stoll him from me while i was dateing him (and before u click a diff ? no this is not about guys well it is but its not just keep with me here i relly need help ok) so any way then when i kiss him like a peck shes not even goin out with him sh completly blows up in my face and i try to be the nicest friend to her i am allways there for her and im the kind of friend if u need someone to come bail u out of jail at 2 in the moring i would be there in aheart beat i have takein her to disney world i paid cause she uldnt afford it i have been there for her thro divorce and everything and the whole time i have been friends with her i have keep up with all of her crap she treats me like a dog and we have a good time every few days dont get me wrong shes a relly sweet girl just shes the meanest friend ever and way so i have put up with all her crap for about 15 years and still best friends with her and now tht i need her (the first thing i have ever asked her for anything) she wont talk to me she broke me and my boyfriend up and is dateing him now she told my mom tht i disrespect her (i dont) she wont even talk to me and i told her tht she has been a real bad friend to me and she said that i was the worst friend that any one has ever had and that she dosent need to take this crap but for some reison she is still my best friend i mean my mom and dad ar getting divorsed on there 20th annavesiry and my grandma died and my mom is an acoholic and i have no one but her to talk to she has treated me real bad and i have benn great to her i fell like a piece of trash around her and yes i have tryed not being her friend but i cant help it she is my best friend i love her but i dont fell like a good friend sence 2 days ago wen i told her that i really need her and shes not there for me and it realy hurts but she just blows me off every time it really makes me mad i dont know wat to do someone help plz!!