I'm not sure why, but I feel like this. I've already told my FP that he's my FP, he knows about my BPD, we discussed it, a few other people know I have BPD, etc. However, there is this person who is someone I'd consider an acquaintance and we get along well. We're at the same gym, we interact there, we work well together, etc. He knows I see a therapist and doesn't give a shit; he's seen one too so he hasn't been weird about it or negative towards mental health. Never asked why I'm seeing a therapist, was fine with the explanation of "I'm dealing with shit". I've never told him I have BPD or OCD or anything else related to my struggles, self harm, and suicidal ideation/attempt, the only other detail that I've shared is that my FP (who this person knows/is friends with also- long story) has helped me with the shit I'm dealing with and has been there for me. But I've never told this acquaintance that my FP is my FP because then I'd have to explain a lot of BPD related things and that's getting into the oversharing/not necessary to share region. 

Now I feel that I should tell this acquaintance of mine that my FP is my FP and that I have BPD. I shouldn't feel this way because it's not really necessary to share this info with my acquaintance, but lately I've been feeling like this acquaintance notices my attachment behaviors to my FP and is wondering what that is. I just have this feeling that my acquaintance is making assumptions or something and I'm just paranoid of what those things could be and I want to squash them at the start. I'm not sure what to do and I'm not sure if this will just end up a self-fulfilling prophecy if I try to explain things to my acquaintance.