Is anyone else overly dizzy ?

I'm 25 and have been experiencing frequent episodes of dizziness for many years. These episodes occur unpredictably, even while sitting or lying down. The sensation resembles vertigo, as if I've been spinning and suddenly stopped, or a sudden feeling of falling—especially when lying down. I'm unsure how to manage this and wonder whether it's a common experience or if there's an underlying cause.

I must say, I am diagnosed with rebellious anxiety-depression syndrome.