A number of different things can cause dizzy spells.
The aim is to try and find out what is behind it, and correct the problem.
For example:
Low blood pressure can cause dizzy spells. You notice this most when you stand up after lying down.
Hyperventilation can cause dizzy spells. Some people hyperventilate when they get highly stressed.
In your situation, is there any indication of what is causing it? is there anything which triggers it? If it can be narrowed down, correcting it will be much easier.