My dog just looked up from laying on the floor and shook his head back and forth in a seizure sort of way. He did it once last week. Is this something to worry about? Otherwise it has never happened before.
I'm not sure how people online can help you with this, having not seen it and just having a one-sentence explanation of it! It could be possible your dog was just shaking his ears?? But if you are sure it was a seizure, then go to your vet.