I too have struggled with being an outcast and with not being good enough for my parents. I realize now that both of my parents were seriously emotionally hurt as children, and they were (and are) doing the best they knew how, given that they were so emotionally wounded.
As a child I coped with it by excelling in the only way I knew that they would approve of me (which was doing well in school). To this day education is extremely important to me.
I think that it is really important that, if if you feel like there is nobody in your family that you can run to when you feel bad, you need to find someone outside your family who you feel comfortable and safe with. You need to find "surrogate parents". You need to understand that just because you aren't good enough for your family doesn't mean that you aren't good enough for anyone. You need to find the approval you crave from someone else.
You need to work on forgiving your family, realizing that they won't change. Remember that forgiving isn't for them, it is for you so that you can let go of the hurt. You need to understand that you don't do anything for them to feel this way, their emotions are about their own pain, not about you or anything you have done or could do.