I'm so glad the Doctor 'got you' and you connected! Thats going to be a great help to you.
You're right: the NPD family information gives you an idea of where you came from and how you got there. Dealing with your addiction to her (or any person, place, thing, or process) brings you to the place where you deal with what YOU'VE become. There are a few names of what this is called: codependency, love addiction and Adult Child stuff are the main ones. The 12 steps are very helpful in this situation, and you'll have a leg up on that because you already believe in God.
In a nutshell: You boot her out of the place where you should worship God instead of a human. Look at the definition of worship
, and you'll find the true description of your behavior toward her. It doesn't mean that you've liked your behavior or even liked her, but you've acted like she is a Higher Power. Interacting with her, around her, about her, against her, talking about her, thinking about her...."her" is the common point, and it's just too much. You're trying to push a human into a God-sized hole in your soul, and it never works. So, the goal is to put God back in His place, and give the care of her over to Him as well. When God is the Higher Power, then you can trust Him to take care of her......and you don't have to. You're not pulling the trigger on the saddest girl in the world, you're stepping aside so that she can get the help she needs (which she won't do as long as you're in the picture). And you trust that God will work it out in a way you really don't have the power to do.
So, thats the mindset. How do you do it? Detox. Go back to NC and know that it's forever. Terminal. No messing around. One Day At A Time. Surround yourself with friends & activities. Get online into the blogs and chats and spend your time there instead of thinking of her. Use the Intrusive Thought Elimination technique again and with vigor. Be very, very tough on yourself. The hardest part is the first few days, but after that it will be easier. You 'bring the body and the mind will follow'. Physically move yourself out of your patterns in as many ways that you can....don't laugh, but it even helps to brush your teeth with the other hand! Change your movements so that you don't keep running into triggers.
Here are some new resources for you for this phase:LAAgreat articleanother great 'how to' with resource list
Good job on going to the Doctor and telling the truth! This is fixable, James, and you can do it. I'm really happy for you.