Hello again Clueless,
You seem to be able to observe your own behaviour with a certain amount of lucidity and also to be able to realize quite clearly that something is wrong. Those behaviours are not often present in people who suffer from NPD.
Depression often comes along when your emotional alarms are signalling endlessly and they are not being answered. Repression of feelings and memories, dissociation, distancing/withdrawal and narcissistic defense mechanisms can all kick in at one point or another to give you clues that something is not settled in your psyche.
I would suggest that you go see another therapist to talk about depression, try to find out maybe if something hasn't gone wrong in your childhood, or if you haven't suppressed a terrible memory. Again please, I am no expert, but I can relate to some of your symptoms and behaviours and it does definitely tell me that something is not right and that you need help to sort through all of this.
The fact that you are worried and that you are trying to find solutions means that you are on the right path. Take really good care of yourself, take all the time you need to make yourself feel better. Try avoiding situations or people who trigger negative emotions where you lose control or you lose your sense of self. Get some help. Take really good care of your-self. Post here often, read up on different subjects : NPD, emotional intelligence, voicelessness, repression, dissociation, depression, etc. You mind find clues and relate to some ideas. Listen to your emotions, they can give you a really good indication of what's wrong.
I wish you good luck.
nihil