BPD tend to exaggerate everything, a down day is major depression. They also get super close to people very quickly. When they get mad they can be vengeful.

I knew a BPD woman, she acted very immature and was always getting the latest fad diagnosis. Once we were at a meeting and deciding on a lunch, it had been resolved and suddenly she spoke up and says she can't eat that she's a vegetarian.....shes not, just wanted the attention, and the lunch debate began all over, it took much longer to resolve than it should have.

Like any illness there's degrees of severity, she sounds like a very severe case, the fact she knows her diagnose but doesn't seem interested in changing is telling. Just because you are nothing like her doesn't mean you don't have BPD it might mean you've a much milder form. Just like BP varies among all of us.