It sounds a lot like what I have been going through. I feel dizzy-like, as if the whole world is spinning, and it feels like my brain is being shot full of novocaine, like buzzy, or a brain zap. and the only way i can explain the episodes is "somethings really not right" and after an episode, my whole body shakes and tremors for up to an hour afterwords. I have managed to figure out that I have Postural Orthostatic Tachycardia Syndrome ( my heart rate goes too fast when i sit or stand, especially when I stand) Does your heart rate go up when you stand? (my laying down heart rate is like 80-85 and is 120-150 standing). However, the Postural Tachycardia doesn't explain the vertigo and head zaps and shakiness, but it appears that that mysterious condition has triggered the Postural Tachycardia, and maybe the Post. Tach is something we have in common too....??
Thank you, best of luck (: