My dog was diagnosed with idiopathic epilepsy ~2 years ago. I must admit that I am surprised that your dog had such an extended shaking period after the first possible seizure episode. And, now you are seeing other symptoms like stiff legged-ness without any observed seizure event.
I am certainly not an expert, but what you describe is very different from the post-ictal states I have observed in my dog. In my dog, the post-ictal period is typically 5-15 minutes and it usually consists of loss of coordination. However, in the case of the most severe seizure he has ever had, he experienced confusion, loss of motor skills, temporary blindness for about an hour or so. That seizure was his first seizure and was, by far, the most intense one he has ever had.
My dog is now medicated, and as huntergreen pointed out, once we got the dosage correct, his seizures have been under good control. But, even before he began medication, his seizure events were spaced by a good 3-4 months. We decided to put him on medication only after he had 3 seizures on the same day after months without even one seizure. That was it for us.
I am concerned that your dog had a second so quickly following the first possible seizure event. Our neurologist would likely advise you to start medication NOW due to the “kindling effect.”
Anyway, just thought I would share some of my experiences. My dog is doing great! You would never know that he had epilepsy. He is active, engaged and just a fantastic companion! But, it is important to take seizures seriously and seek out a specialist/second opinion if problems persist.
Wishing you and your dog all the best!
P.S. It is great that it sounds like you are keeping a seizure log. Very important to do so!!! Let me know if you need more info on that.