dog is having seizures

I live in a very small town, the vets aren't open on weekends nor in the middle of the night. The nearest open vet is an hour and a half away. So I need advice if I should take the trip tomorrow or wait till Monday. But about my dog, the first time this happened I really didn't know what it was because it happened in the middle of the night. Well a month later, tonight, he was next to me on the couch and was swaying back and forth. Then he's legs for straight and I lifted him and he fell backwards. He wasn't responding to me so I just held him, he was shaking. A couple min later I see him looking around and slowly start to gain his function back. He got off my lap and walked around and shook it off. He's now outside running around with the cats like nothing happened. Is this life threatening? Should I take the trip tomorrow? Any one experience this. And I know it was a seizure because I looked up dog seizures and it was exactly the same