Did my cat just have a seizure?

My cat suddenly started meowing very loudly, crouched and stretched out his neck.  I rushed over to him and he fell onto his side and kind of curled and stretched out his limbs, but his body was limp.  He was meowing softly....I rushed out of the room to contact my vet and my husband stayed with him.  While I was trying to reach my vet (who's office was closed!!!), my husband shouted that he was pooping and peeing!!! 

He seems perfectly fine now.  Like it never happened.  Obviously I am going to take him to the vet on Monday, but I am freaking out.  Does anyone know what may have happened?  He is only about 5 or 6 years old.

It does sound like a seizure. D you have an emergency vet in your area that you could take him to?

He is now acting like nothing even happened, so there is nothing an emergency vet can do.  I am going to take him to my vet on Monday.