What Causes Dizziness In Person With Migraine?

I have been dealing with chronic headaches and migraines for 3 years. Just lately I have started to become dizzy. It starts when I wake up. The last time i had it I took Excedrin and it faded within a few hours. I took some and its not quite going away. What should I do and why do I keep getting dizzy? It keep interfering with my every day activities.