Children of Addicted Parents and People

Hey,,
I really just dont get my parents.
i dont speak to my dad anymore, or his side of the family, becuase one my Nan hates me, and 2 because i just dont really want to be associated with them anymore, especially my dad.
so the otherday i got a phone call of my nan randomly out of the blue, with her screaming down the phone at me telling me that everything is my fault, and its my fault my dad drinks and uses drugs, and now its my fault he is suicidal, and she said that i am just like my mum a selfish cow, and am going to end up like a low life like her. i just dont understand why everything is my fault when i havnt techniqually done anything wrong, and i dont ever want to be like either of my parents!!!
i just wish they would leave me alone.
my nan doesnt understand anything, she doesnt know about what happened at home, she just goes by what my dad says, which is a load load of lies!!
and i decided not to speak to him for my own reasons that knowone else knows about, and for some other reasons that people do know about
i really just dont know how to handle them sometimes .....