Hey @unwind, I am sorry to hear that you have been feeling concerned about your behaviour and have found no clarity. It must have been quite confusing and upsetting for you I imagine. Good on you for seeking out further support, I know that can be hard sometimes.
What @Eden1717 mentioned is relevant. In addition to that, I would add that sometimes a diagnosis may not fit or may not be completely necessary for treatment. It depends on numerous factors, so you are entitled to ask about a diagnosis which could lead to a discussion like this. They also might then be able to explain their reason for not giving a diagnosis, as there can be many.
If you lead with your symptoms, using your own wording and direct experiences, it can allow the doctor to make an objective assessment. However, if you lead with your thinking around it potentially being associated with BPD, it might provide them with context, cues and a specific diagnosis to explore.