To be honest, my exBPDgf was one of my very best friends. We shared so much in common and had awesome adventures, and could bum out all day and still be happy. So part of me is like, why didn't you just talk to her, things could have been OK friends wise... .
I really don't want this to sound harsh, but did you really have that much in common? Or did she just mirror your likes and interests? Because, unfortunately, that's one of the things that happens in relationships involving a person with BPD. It's part of what sucks us in. They lack a defined sense of self, so they morph into what they think we want them to be. A whole lot of people on here have experienced it. Our exes loved one set of things when they were with us, but a completely different set of things when they moved onto their next partner.
The other problem is that friendships with a pwBPD face pretty much the same problems that romantic relationships do. There is a reason that most people with BPD have very few friendships that get far beyond the superficial level. It's just as draining and one sided as dating them. You'd still experience the same cycles of being painted black and white; Still have to deal with the one-sided nature of the relationship; Still have to cater to her demands, lest you face the consequences.
Perhaps I should have just talked to her, broke N/C, and just lived my life back in that same old town
Mutt's right. You're going through a lot of huge transitions in your life, all at once. That can be overwhelming for anyone. I know when I've gone through similar events in my life, I was left feeling vulnerable and exposed. Those feeling left me very open to falling into old, bad habits, and my ex was the worst habit I had. Don't make that same mistake. I know it's tough, scary even. I'm sorry you're going through it. But you can make it through. Just try to stay focused, and stay strong. Things will get better.
Best luck,
Rise