How do I deal with my family?
Your mom loves you, that's why she's paranoid. About the bike thing tell her mountain bikes don't interest you anymore. And for the races tell her how you feel, and that you did your best, nobody's perfect. Meanwhile, have your friends over.
About your dad, tell him you will get a girlfriend when you're ready.
About your sister, tell you freaking parents about how she behaves! She and that clown has no rights to hurt you, and your family's stuff. If that fails, when he comes over, get out of the house, or stay in your room until he goes home.