What could cause of my dizzy spells?

Nausea/dizziness: Many causes possible, such as Migraines, inner ear problem, motion sickness, low blood pressure, high blood pressure, diabetes, early pregnancy, hyperventilation, etc. My recommendation is to seek medical attention if symptoms severe or other symptoms are noted.

Many causes.: Dizziness can be either vertigo (sensation of things moving) or light-headed. There are many possible causes of vertigo. These range from inner ear problems (vestibulitis, benign paroxysmal positional vertigo) to vestibular migraines to problems with the brainstem (such as strokes). Light-headedness can be caused by standing up too quickly, dehydration, or low blood counts.