As for the 'not treating you any more', it seems essential to find someone else. From what I have personally experienced with mental healthcare, there are providers who do not want to treat us because it can be a long time of treatment (for some) and our heightened emotional states can be very challenging for them. And, we can be very manipulative. I don't mean this (manipulative) as though we are 'bad'. I mean that we put on that impression that we are 'normal'. We hide what is really going on in the inside. Then, we tend to divert attention (manipulate) to something else to avoid getting the truth out. I don't want people to know about the 'real me' with the overwhelming feelings of being different, not fitting in, being seriously depressed, getting angry quickly, becoming hysterical and crying quickly, desperately wanting them to like me and praise me. [Just a few of the deep mind desires I have.]
As for the being diagnosed with BPD, I would like to suggest avoiding fear of labels. Keep an open mind and do some research. BPDers do not all have the same exact behaviors/thoughts. And, recognizing the symptoms in ourselves can take time until we can identify them in us. If you are BPD, and you know that now, constructive steps can be taken towards healing. But, we can not fix what we don't know. During your adventure down the understanding your thoughts/feelings/emotions path of 'mental health', seek the 'truth'. Because it is the truth that will allow us to move on. We can make a plan for healing if we can find those underlying issues. When there are labels, there are often processes that can be followed that have been proven to help people within that 'category'. I don't think it is such a bad thing to have a label. Now that I know more about myself, I can start the process to move on and heal.
Keep an eye out for the truth!