IDK --- its all just a thought. I do know I'm not a narcissist. But, I'm willing to look into BPD.
A trained professional would consider all possibilities--co-dependence, anxiety, bpd, narcissism--and recommend a course of treatment to get your headspace as healthy as the rest of you. You have so many strong, positive traits that come across in your posts. I am so rooting for you. If a friend's dog had a broken leg, I suspect you'd prefer them to call a veterinarian rather than read up and attempt to treat it themselves. Even if they once saw a bad veterinarian who misdiagnosed something or took advantage of them. Anyway, whether you do or do not seek a professional, we're here for you and will be cheering you on.