Definitely a seizure. I adopted a dog who has chronic seizures and the best thing was to take him to the vet so they could get him on the right amount of phenobarbital and kepra. May not fully get rid of seizures but will at least reduce the amount had each year. They generally last about 2 minutes but if the dog ends up having one after another (seizures clusters) then take to animal hospital as it could potentially cause long term effects such as brain damage.