As far as remembering what it felt to be like in all kind of different altered states, I can remember that quite vividly. From alcohol, to pills, coke, meth, the subtle differences between the different anabolic steroids, the hallucinogens, etc.etc., they were all quite different. The one thing they all have in common is they take you further and further away from reality.
The human brain is not made to function in very altered states for extended periods of time and that seems to be why all substances have withdrawal profiles all their own. The brain is trying to normalize but it almost seems like it has to relearn what normal even is. I doubt I'll ever forget those feelings.