They say I act white?

I've always been called 'white'. Even though I'm pretty sure I'm black. People have said so many mean things to me that I had to learn to shake it off or I would be crying every day. But really, it's not the kids at my school or anything(mostly because i've been home-schooled since I was in the fourth grade, I'm in seventh going to eighth right now), it's my family. I know how crazy that must sound but it's true. I don't listen to rap music like all the other kids around my neighborhood. I also talk proper and I like pop and R&B and I watch Disney Channel(Sonny With A Chance, Suite Life, Wizards) a lot. I watch other stuff too, like MTV(My Life As Liz), Fox(Glee), Oxygen(Bad Girls Club) but they tell me that stuff is lame and I'm a 'white girl'. My mom calls me that too but I know she's not serious but sometimes it still hurts my feelings. My Cousin(let's call him cousin A) is 26 and he calls me white girl ALL the time. It's like my nickname or something to him. I always just told myself he was joking and would laugh it off but still, it hurts. Tonight, I was on the phone with a friend and somehow we just started talking about it. (He's friends with my other cousin(cousin B) who is a boy and is the same age as me) He started talking about how my cousin B talks behind my back telling him that I act white and that I'm annoying with the way I talk. Okay, little info about my cousin B, he's straight ghetto. Bottom boys and all that rap music like Waka Flocka Flame, that's him. I remember getting into a pretty heated argument with him about it telling him to F off and leave me alone. He then told me that our family members agreed with him about me acting white. He said some REALLY mean things and I ended up crying in the bathroom for ten minutes straight. It just so happens my cousin A the one who calls me 'white girl' was there and I asked if he could take me home considering he lived pretty close to where I did.(I asked my cousin B mother but she said she wasn't going out and walked away from me) Turns out, she doesn't like me. My friend said that when I'm down at my cousin B house and his mom isn't home yet she calls before coming home from work to make sure I'm not there and that my mother has came to pick me up. He also said that the day I was in the bathroom crying my eyes out my cousin B asked my cousin A did I act white and he said "Hell yes!" and other VERY mean things about me. I was literally crying on the phone when he was telling me all of these things. So the thing is we are going to Virgina next weekend and I was suppose to go with my mother but now I'm not because she has to work so I'm going with my cousin B and his mother and their side of the family, who don't like me. They didn't even invite us we didn't know anything about they were going out of town until my uncle asked if we were going and my mother said nobody invited us, so he did. And they got PISSED. they wouldn't talk to us, wouldn't answer our calls, nothing. I know they don't want us to go, i can feel it. I hung up the phone with my friend and literally cried my eyes out again over this stupid bull crap. I really don't want to go with them now because of all the things they have said behind my back and I know now how they feel about me. I was also trying to decide if I should tell my mother about all this new info I found out. What should I do? And do you think I act white?