I know what you’re going through. I’m an ABT(American Born Taiwanese), and my parents wanted English to be my first language so that I could function more easily here in the states. However, it’s been a struggle to retain the little bit of Taiwanese I ever knew, and as for Mandarin, forget it. While I sympathize, the bottom line is that if you really want to learn a language, you have to want it badly enough to struggle through the discomfort of speaking it (badly) every chance you get, even if it is with the very people who make you feel bad for not being fluent. But even if you don’t manage to do that, don’t beat yourself up about it.