I was thinking about the same (BPD) with respect to myself and I also thought that my T wouldn't tell me this at least at the beginning... But once, I just wrote down my stupid thoughts and the process of really fast calming down and I sent it to T... Surprisingly it didn't terrify her at all (and I guess it would terrify me if someone else wrote something like that) and she said that it is quite "normal" for people with such experience and that she really doesn't think that I could have BPD as I always control myself very well and I only think about something but I'd never act on it (or even let someone know about it)... But if I was diagnosed with BPD, I guess it wouldn't change much as this label wouldn't change my behavior I guess, so I just stopped "bothering" myself with thinking about 100 different diagnoses which I might have... Because in addition to c-ptsd I see in myself some traits of dd, depression, bipolar, gad etc. and sometimes I am really surprised that my T said that maybe if she had to put any "label" on me for the insurance reasons she would go for dnos but nothing more...
And since I stopped worrying about it - it is better