I think the first thing you need to do to get them to accept you as you are is to be yourself. You're parents sound like good people that are just concerned about you. I hid my mental illness from my mom for a long time. I finally got tired of not being able to talk to her about it, so one day I sat her down and said, "Look, we can talk about this, it's okay," and I think our relationship got better after that. Plus, I understand about the bisexual thing, it took me a year of dating my wife (I'm female and bisexual) to come out to my mom, and all she said was "So?" You may find they are more accepting than you think. I wish you the best of luck.