Are you seeing a Therapist? I sounds as though you are a bit overwhelmed with things in your life right now and are regretably taking it out on your friends and family.
I have been guilty of doing the same, however, when I know I am in a "mood" or feeling upset about something, I don't talk to my friends at that moment or for the day if need be. As far as FB goes I try to keep that as a place that is mainy for positive and optomistic conversations as most people I am friends with on there are not tapped in on what BPD and the moods that go along with it are all about. I reserve such feelings and conversations for this site because I know there are tons of people who can support and understand what I am going through. This is just a suggestion on what works for me, i.e. I keep my boundries in order not to tarnish or alieniate friendships that may not be solid enough to take the abuse I know I can inflict!
I have learned some self control in the past few years, as I too have lost many good friendships, some now, that I am trying to rebuild, after years fo not talking to them. It's a hard lesson to learn and I still have to catch myself trying not to take my issues out on others!
I hope things in your life settle down soon adn that you can talk to someone who will really understand and can help you work through these difficult times! We are here for you at lest to listen and can give you our life lessons. Good luck, I hope you can work things out with your friend!! (((((((psychochick))))))