Can you tell me how i could make my family stop bringing up the fact that i'm gay or bi when i'm actually straight?

May not be possible: If this is as you describe, there's some serious pathology. LGBT still carries stigma in many circles. This may be their way of expressing disappointment for some reason, or a fixed idea from mental illness. You've told them the facts and how it hurts you. Next time, you might say, "I have no idea why my parents say this about me." Get a marketable skill fast & prepare for life on your own.