I don't know much, but we do have some things in common. Hope it helps.
I suffered hypoxia at birth, and had grand mal seizures as a small child when I had a fever, until school age. I was in the clear for over 15 years until out of the blue I had a grand mal in college. Like you, my EEG was also clear, the only reasonable explanation was hypoxia so they put me on dilantin and left it at that.
Worked well for 25 years, only a couple seizures and that was when I let myself get run down. Cannot stress enough, be sure to get enough rest, especially in times of stress. All my seizures were when I was tired. Don't drink excessively. Completely avoid non-prescription drugs. That much advice I can offer based on both doctor advice and personal experience.
This summer I have had 3 seizures, after ten years of complete health. Doctors are speculating that the dilantin is not working properly anymore. My med is being changed, and am having MRI to rule out cyst or tumour. You mentioned that you have headaches, has your doctor considered an MRI?
Have you seen a neurologist? Many times doctors cannot definitely pin down a cause for seizures, but commonly can control seizures with drugs. I know what you mean about not driving, it is a major problem. However, in the past things have always worked out after a year or so, and I hope they do for you too.