I also get the symptoms of brain fog, dizziness, palpitations, speech, skin, eyes, hypersensitivity etc, just like 'Devastated' and 'JRD' describe in their detailed posts.
I also experienced the restless leg syndrome that 'rock27' describes when my POIS was at it's most intense.
But one thing i haven't seen mentioned yet is that my metabolism seems to go into overdrive during my POIS. I also loose muscle tone very quickly (could be fluid loss). My brain fog also has some kind of weird race condition to it that makes it very hard to focus.
Another unusual symptom is the amount of moisture in my breath during POIS. I often fog up a window or mirror intentionally. I always assumed this has sometime to do with the racey metabolism.
(note: my POIS symptoms are 80% gone these days. I haven't tried any of the treatment methods on the forum yet, although i plan too. The symptoms just gradually elevated over 15 years of managing my diet, lifestyle and symptoms)