Being diagnosed is scary. It scared me for years. And that's completely understandable! Take your time with it. Let it sink in a little at a time. It took me years before I could accept it as my diagnosis. It may not take you that long, especially since you're so educated on the subject beforehand. I was getting my BS in psychology at the time of my diagnosis and I still didn't know much about BPD.
I don't have much in the way of advice in the relationship arena. Relationships are especially difficult for those of us with BPD, so maybe a therapist could shine some light on the subject.
And welcome to PC!