Thank Teamn, Mihaela and Andthistoomustpass - your replies are super appreciated, thank you so much for your support and advice.
Mihaela, it's nice to hear someone else experiences this sort of thing too. Yeah, I guess, I am forgetful, but that tends to be when she surfaces around other people - she just doesn't absorb what they're saying because she's so focused on maintaining her upbeat presence. However, I think I'm more inclined towards andthistoomustpass's in that I'm hesitant to think that I have a complete disorder - while I may have certain symptoms of a certain condition, I don't feel justified in saying I have the disorder, as this almost seems to make and accept this as a permanent and categorical thing (even though I know you, Mihaela, said these things can be temporary). I have had periods of an extreme low mood, and am very close to self harming, so she could be a manifestation of a self-defence mechanism.
Thanks andthistoomustpass, I'll check out MIND and keep what you said in mind (pun intended xD). While I want to seek someone professional, part of me's scared that they'll put me on pills that will just make the situation worse. At the same time, all of the me's agree that I need to talk to SOMEONE about it (hence I ended up on here - thanks again guys). But then there's also the fear that that someone will put it down to an over-active imagination. I think, ultimately, I need release, somehow, and I'm trying my best to stay away from self-harm, but the temptation is so very compelling. Think I just need some quiet, empty haven where people know exactly what I'm going through, if such a place exists.
But until then, research, research, research, and then when that fails, distractions!