My Boxer Just Had What I Would Call A Seizure.

My boxer just had what I would call a seizure. He stepped off the couch and immediately fell over and he had no control over his body. He was trying to stand up and couldn't. I got in the floor with him and kept him from moving. He couldn't even control his bladder and went in the floor. I held his head for about a minute and he slowly came around and stood up. He wasn't walking very well but by the time I got up to get him some water h had gotten up and went out the dog door and went to yhe bathroom outside and came back in. He also was slobbering a lot. This has happened a few times in the middle of the night but this one seemed worse.