I've been looking for something that fits my symptoms for AGES. Recently I found out that what I've been calling "emotional detachment" or "backseat driving in my own head" has a name in psychiatry. (I probably ran across it in my psychology classes at some point and didn't understand it fully.) It's called dissociation.
So I started googling personality disorders with that as a symptom. I figured I was looking for a PD, because I had basically ruled out everything else that made sense. Depression and bipolar disorder didn't fit all my symptoms and most of the rest didn't even make sense.
Ran across BPD, also referred to as Emotionally Unstable Personality Disorder. Symptoms include dissociation, inability to control your emotions, feeling like your emotions are in control of you, and as a result of the lack of control, your social interactions would suffer. Impulsivity is a big issue with people with BPD, as is something they call "splitting": basically I experience it as only seeing one side of a person at a time. I'll look at one person in particular-- who shall remain nameless-- and I'll either go "I love them and they're awesome" or I'll go "omg you've done this bad thing you're fucking evil" and I know they're not flawless, I know they're not evil, but I can't see both sides at once. It explains my anger issues, my embarrassing inability to control my reactions when I'm upset or excited or angry, my inability to decide how I feel about myself or what I want to do with my life, my anxiety issues, my occasional depressive states, my absolute terror at the thought of being alone, my pervasive boredom if I don't have something really involved to do, and my urges to self harm (though I've gotten better at managing those).
So I go see my therapist, armed with this information, and basically what happens is once she realises I won't be offended she says "yeah, I have that down as a possibility in your notes from a long time ago."
But the immediately important part is that I have an explanation and a jumping off point for treatment
Update: so I totally misunderstood what my therapist meant when we agreed it was an unofficial diagnosis. It is definitely what I have. We just can't tell insurance that because they will then stop covering my therapy. Because personality disorders are not caused by brain chemistry, insurance apparently thinks it's less valid and stop covering treatment. Even though therapy is literally the only effective treatment for a personality disorder. They know it'll take a while to work through and they don't wanna cover that much. Dickbags.