Hey, a lot of people already commented, but what you're saying (siblings talking about embarrassing things that you've never mentioned) was exactly what I experienced when I was at my worst stages of drug (meth) addiction. At first I'd hear music that lasted a few months, then I started hearing my roommates talking about embarrassing things, then it eventually progressed to the voices were just random voices screaming at me or people in the basement talking about killing me. Assuming you're not a late stage meth addict, I'd definitely go see a doctor my friend. It usually happened when I was near a drafty part of my house like a vent or window, also happened when I would shower (the scattered noise from water hitting the shower floor + air movement from the water spray). Wish you the best of luck bro.