Thanks very much for your response.
I assume that bipolar personality disorder is on a scale? My gf would often display many of the traits mentioned but not to an extreme, frantic extent - she always seemed very laid back, even unenthusiastic, not terrified of abandonment - was often of the mindset "you can come over if you want to.... whatever", but then be very loving whilst I was there.
She often found it very difficult to communicate about troubles in her past - her father leaving the family when she was young - and about her eating disorders (linked to mother making comments about her weight), but talked with me more than she ever had anyone else.
She would switch from being unresponsive and quite rude (but not necessarily cold) to loving within the space of half an an hour - whenever I showed a reaction i.e. went cold on her, she would switch back to loving and start to console me, not knowing what had happened.
Do you think that a diagnosis of this type is more consistent with the above information than her simply being a dramatic individual with poor boundaries? It seems like she is displaying an extreme form of pragmatism - wanting us to work and be together but not seeing it as a possibility given the distance. Is it possible for a secure "normal" individual to experience such intensity of emotions with someone and then just seemingly move on when in a completely different environment with a lot of distraction, particularly when 20 years old? To say that she is loving her new life and not to think of her old within 3 weeks of parting!? Even if it is her dream lifestyle.
She often displayed a lack of enthusiasm and seemingly a lack of caring, particularly over the phone, but I wouldn't describe it as bad as cold on these occasions, just unconcerned - is that consistent? She could seem very distant sometimes, not seeming to be at all dependent upon me - a typical evening may start with me visiting, her seeming fairly unconcerned by my presence, then settling down for a meal with limited conversation and then cuddling on the sofa before bed - progressively getting more and more intimate as the evening went on.
What upsets me in addition is that she was apart from her bf of 2 years for 1 of those years yet did not cheat on him until the very end of the relationship - yet for us our time apart only lasted 3 weeks! Despite this, she told me that she loved me more than she ever had him and that our relationship redefined the emotion for her. Considering our discussions over children, marriage etc, surely she wasn't just caught up in things?