Last night, when I turned over in my sleep, I suddenly felt dizzy and lightheaded. When I opened my eyes, the entire ceiling was spinning wildly. I thought I was going to die. I asked Doubao, and he said it was benign paroxysmal positional vertigo (BPPV), which is when the otoliths in the posterior semicircular canals dislodge. I'd never heard of this before. He also said it wasn't a brain problem and wasn't dangerous. He taught me a method: tilt your head 45 degrees to the right, quickly lie down, and when you feel less dizzy, tilt your head 45 degrees to the left. While lying completely on your side for 30 seconds, sit up. This will cause the otoliths to return to the utricle. I have to say, Doubao is a complete winner when it comes to everyday questions.