It's possible that your t doesn't want to give you a diagnostic label that could prove to be discouraging for you.

A had a psychiatrist diagnose with me BPD after a short hospital stay. However, when I asked my t about it, she said that she and my own psychiatrist do not use the BPD diagnosis because there is such stigma and negative attitudes toward it. Also, she said that while I had features of BPD, she believed they were manifestations of my PTSD and that once the PTSD calmed down, so would the BPD traits.