kittens, I had a seizure like you are describing about 22 years ago. I was walking through the mall one minute, the next I was being wheeled out of an ambulance into the ER. I was clueless, just like you, as to what was going on. I can relate to how frightened you were. Luckily someone was very close by who actually put something in my mouth to keep me from biting my tongue. I remember sleeping afterwards for something like 18 hours, I just couldn't stay awake.
I had Cat Scans done, EEG's and I'm not sure if I had an MRI or not. But nothing showed up. I never had another seizure, (except when I was going through withdrawals) so hopefully this is a single incident like I had.
It sounds like your doctors are going to thoroughly investigate the combination of meds along with any other possibilities. And yes, thank God you weren't driving when this happened. That's something none of us want to even think about.
God Bless & Prayers are being said,
Judy