Is my dog having seizures?

I'm no vet, but I believe my 8 year old female English Bulldog (Gracie) is having seizures... She had an "episode" about a year ago while she was being watched by my wife's friend (Holly). Holly called us and said how Gracie was "shaking and was stiff". Gracie also threw up around the same time. Now tonight when my wife and I got home from work, Gracie was up on the couch and she was shaking and stiff. The "shaking" was more like excessive twitching. She was very wide-eyed and was drooling quite badly. After she quit shaking she wanted down off the couch so I helped her down but when she tried walking across the room, she was stumbling all over as if she was drunk. She made it to the kitchen where she sat down and my wife and I rubbed her all over to calm her down and after about 5 minutes, she was back to normal like nothing ever happened. Any dog experts or veterinarians that know about this kind of thing please advise. By the way, we're making an appointment at the vet for her tomorrow morning. Thanx.