It is difficult to define the mental disorder one may have, especially when self-diagnosing. There are many mental disorders, and many of their symptoms are very similar to each other. Sometimes, we may believe we have a certain disorder, but in the end, it turns out we have another because their symptoms are similar.
Before I went to therapy, I thought I had BPD because I had unstable relationships, idealized my friendships, devalued those who hurt me, had very sudden mood swings, and that feeling of being abandoned. However, when I went to therapy, it turned out that I actually had ADHD because some BPD symptoms exist in ADHD, but in my case, I also have ADHD symptoms like inattention, difficulty focusing, disorganized thoughts, excessive talking, and impulsivity. Therefore, my diagnosis was more focused on ADHD than BPD.
And even so, I still have doubts if I have BPD. I've watched a lot of videos and articles about mental disorders, and I've started to wonder if I have both.
Similarly, my hyperfocus on learning about mental disorders has helped me understand people a bit, but I'm not an expert on the subject, and I'm sure I have a lot more to learn. So, it's great to be knowledgeable about mental illnesses, but it's advisable to have someone diagnose you to know what you truly suffer from, regardless of whether it's not what you expected.