Perhaps at this point it would serve you well to develop a new outlook on your DPD?
Clearly you're unhappy with the state of your mental affairs, but (I'm sure you know) the stress of having DPD will only further worsen your symptoms.
It's something you'll have. It's something that has been employed by your mind to protect you. It's something that sets you apart. Find acceptance and pride in it. It sounds like a flippant idea I know, but if you have no where else to go, where else CAN you go? Perhaps it's time to change the internal opinion of the external if the external is untouchable. Now you can only consider your perception of DPD. I've never particularly found the desire to be attached thus I am not at a loss for dissapointment in not finding it. If you can accept it (as easy and hard as that may appear) as opposed to putting so much effort into reversing it, you will perhaps find yourself a much happier character. Not only that but if you relieve yourself of such stress the symptoms themselves will surely lessen.
In terms of depression I know what I'm asking/offering is difficult without a chemical inbalance, nevermind with one. I also understand that the depression must aggrivate your DPD. I understand that depression is a whole other boat - one I don't think I should offer opinions on due to my lack of research/experience. Are you talking to someone to aid with the depression? Are you taking any medications? What are you doing in terms of the depression?
Either way, if there's nothing else you can do the only thing you can do is change how you feel about it.
Good luck!