Isn't it ridiculous when a p-doc says you won't have withdrawal symptoms from stopping an ssri because the new one is 'the same' as the old one? I mean, if the new one was the same as the old one, what would be the point of switching? Obviously, there are differences between one ssri and another.

If you go off an ssri completely and don't replace it with another ssri the withdrawal can be sheer hell (in my experience). BUT if you switch from one ssri to another withdrawal (again, in my experience) is milder. NOT non-existent, just milder. I definitely believe your mood issues can be from stopping the Cymbalta. Sounds classic to me.