>>I have this impression that "white" people are more confident about themselves

I can assure you that is not true. In fact some people who seem very confident are acually very insecure. And personally I believe that in many cases, people who judge others as "worse" than themselves are really just expressing the same kind of personal insecurity as people who judge themselves "better." I think people who truly are secure in who they are don't care, worry, or even notice whether the people close to them are white, gay, black, straight, asian, extra-terrestrial, or vegan.

Try to take what others might be thinking out of the equation. Don't project your own insecurities onto them, assuming what they may be thinking. Just work on loving yourself and getting your confidence to match the reality of who you are.