Hello, What you are experiencing sounds like Benign Paroxysmal Positional Vertigo (BPPV), one of the most common causes of vertigo which causes short episodes of mild to intense dizziness, loss of balance and unsteadiness, a sensation that the world is spinning, nausea and vomiting, and sometimes migraines. It is bothersome, but rarely serious, except for the increased chance of falling. The causes are often unknown and can happen spontaneously, but sometimes it can be a consequence of head injury, damages to the inner ear, or even a prolonged positioning on your back (i.e. dentist s chair). The reason for the dizziness is the dislodging of small crystals in the small structures of the inner ear, so the treatment is a procedure performed at the doctor s office called Canalith Repositioning, which consists of simple and slow maneuvers for positioning your head. Your doctor will likely teach you to do this at home if necessary. It is very important that when experiencing these episodes you sit down immediately and be aware all the time of the possibility of suddenly losing your balance. I wish you a fast recovery,