What Causes Sudden Dizziness And Feeling Of Spinning?

Okay so I was sitting in my floor the other night watching TV, not moving or anything just sitting, when i felt something move or break loose in my head. Kinda like a sinus opened up. Immediately after I felt very dizzy and the whole room started spinning for about 5 minutes. Since then I've had these spells off and on for the past two days. Some being worse than others. What is happening to me?