Hi Kelly, just to let you know you are not on your own. Epilepsy is not as common in Labradors as in some other breeds but is by no means unheard of. My old Beth went epileptic at 18 months but lived a happy and contented life until her death at just a few weeks short of 14 years old. In fact, at one time, at my dog club, out of a committee of seven we had a total of five epileptic dogs, a Cross Breed, a GSD, a Sheltie, a Golden and my Lab.
Your breeder should have been very concerned. Although it is possible for epilepsy to be brought about as a result of injury or poisoning there is every reason to believe that in most cases it is hereditary
Think you might find this link interesting
Epilepsy Regards, John