My head is a poorly made snow globe?When microscopic 'rocks' in your inner ear come loose.

From the show

Oh, god... really?

Your sense of balance relies on a surprisingly fragile system. Tiny calcium crystals, or 'ear rocks', are meant to stay in one part of your inner ear. When they become dislodged, they can drift into your semicircular canals. This migration creates a false signal of movement, telling your brain you're spinning when you're not. The result is a sudden, debilitating bout of vertigo from a simple turn of the head. It's a bizarre design flaw with dizzying consequences.