One of my cats whacked his head on a big piece of furniture and had a similar event including seizures and other scary stuff. HE was out of it for a few days, may have had a couple of smaller episodes but is fine and back to his old ways.
I hope your buddy recovers completely, I personally trace it to the head smack and getting a concussion and the brain fog that results.
I will most definitely pray for you and your pup, my animals are part of my family and I understand your pain and anxiety.
I hope that’s what it is, too.