I'm so sorry, Lucy. I'm not sure how it works, but I'm fairly certain that driver's licenses can be pulled for medical reasons, and I would think that this whould count as one.
My grandfather's license was pulled after he had a stroke. (I was fairly young, so I may have misunderstood the family discussion.) It was hard on everyone involved, but definitely for the best. A few years before that, one uncle was seriously injured and we'd lost Grandma in a head on collision where the other driver was an elderly gentleman who shouldn't have been driving.
I hope your doctor can point you in the right direction and get you the information you need on both the medical and license fronts. Big, big hugs and wishing you peace and strength!