my demi had a petit mal seizure from rosemary in chicken one time and the difference in a petit mal and a grand mal is a petit they lay on side and go stiff and a grand mal they shake and convulse. The grand mal is worse. My demi after petit mal was nervous and afraid to walk and just sat there shaking as if cold and scared
broke my heart.
I agree see another vet -- was blood work done to see what is happening if anything?