Did my dog have a seizure?

I’ve noticed my dog lately has been snoring while sleeping and making some strange noises. Today she was sleeping beside me and started making snorting noises, so I picked her up and her head flopped backwards and her eyes rolled back in her head. It was scary and seemed like a seizure. She is over 12 years old and she’s a toy poodle. She seems fine now. I know she is towards the end of her life. :(