Is a concussion bad if about a week after it happened, you passed out and shook on the couch and it sent you to the er and they diagnosed you with convulsive syncope? did i do permanent damage?

Some people will have extraneous movements when they faint. The term convulsive syncope is often used in these situations and can occur in the absence of prior trauma. The "fit" by itself does not reflect existing brain injury or cause it. Please review these events when you see your doctor.

If fainting occurs and the subject remains upright or sitting convulsive-like events may well occur prior to awakening. But if these events occur when supine, it may well have been an epileptic event, and the term "convulsive syncope" is a misnomer. Not clear if you had a concussion from your post. See a neurologist. Do NOT drive, or do activities at heights, until clarified.