My beagle has epilepsy. He had his first seizure at about 1 1/2 years old. We immediately called the emergency vet because we weren't sure what was happening to him - we thought he may have been choking. He was standing up, staring straight ahead and was sort of rocking front to back. They told us to bring him in and as we were rushing to the vet's office, he had another seizure. About $90 and a lot of tears later, we were told to bring him into our regular vet to have his bloodwork checked.
Our vet advised us to wait and see if he had anymore episodes before we had testing done just incase it was an isolated incident and he may have been into something toxic. 6 months later he had another seizure and then 2 more in the following two months. A typical seizure for Bueller involves his body becoming rigid, slight shaking or rocking, excessive drooling and his eyes often look like they're going to pop out of his head. They generally last anywhere from 2-5 minutes. Anything over 5 minutes and he should be rushed to a vet. After each episode he will seem drunk/disoriented for up to an hour afterwards.
Bueller is now taking potassium bromide and has been seizure-free for almost a year. It's an incredibly hard thing to watch your pet endure and there are a few support groups around if you're interested. Good luck with your vet visit.