Please help... my family is mental ?

Even I am the one who was born in abusive and mental family. Atleast you are lucky that no one is physically hurting you. To be frank, don't have much to do with them - esp. emotionally. You are still young, so you have no option but staying with them until you turn 18 and can move out. And nothing you can do to change them. So IMHO, just don't worry about them too much, just only have to do with them for your needs and be nice to them outside, but from inside just don't care. Concentrate and focus on your own life. Pay more attention to studies. I don't know whats your age but if you're above 14 try find a bf. That will divert your interest and you will have more good things to do in your life. Go to school, hang out with friends, spend time on internet and social networking, read good books, join some hobbies or activities go for walk, join activity like swimming, meet people who makes you happy. So in short, though you live with your family but just don't give much damn about them and don't spoil your mind. Focus on your own life more. Develop a bond with your little sister but just ignore rest as much as possible and only have to do with them for your work get done and for your needs fullfilled. If they expect you to help and take care of your sister then do it so that they don't complain and shout on you and spoil your mind. Dont mess with any of them and most importantly don't expect and emotional attachment, love, care and support from them. I know it hurts and sucks but it is better to be practical and thick skinned rather then giving too much thought to all this crap and causing emotional damage to yourself.