Ok, I probably shouldn't be posting, but I'm a bit confused about the difference between borderline and avoidant vs. Personality types. I do a lot of research on personality typing (MBTI and Enneagram) and ISFP's, INFP's, and Enneagram type 4, and probably 5 too, sound a heck of a lot like these personality disorders, yet it's their own personality type. So I don't understand how these are issues. To me, happycheeks, you sound like any number of those types, and I would know, those are my types (MBTI ISFP/INFP, and Enneagram type 4w5), and I relate to pretty much everything you've said.
Enneagram type 4, very very strong emotions, can feel emptiness and wanting to find something else, feel like they're missing something. They're much more focused in their own minds rather than the world around them (especially the 4w5's are, it's insane). From my experiences, and what I've read, there's also a great struggle with socializing, so they shy away from it. These are probably the typical Avoidant people. They may also be quite frustrated with society, I know I am (YAY FOR THE BOHEMIAN lol).
For ISFP's and INFP's (not saying that's your type, you need to find that out on your own) they're probably some of the MOST introverted personality types you can find, especially the INFP's (the idealists), and being an introvert there tends to be few friends you can really connect to.
In relation to your post, happycheeks, I relate to practically EVERYTHING you've said, right down to the making up stories in my head and coming up with multiple characters, this is probably typical type 4 stuff, as they idealize and create idealistic selfs, characters basically. They're also super creative, so creating stories in their heads is pretty easy and probably far more entertaining than the world around them, I know it is for me.
So, I'm not sure there's even a problem, but then again I don't know anything about Borderline and Avoidant other than what I've read, or anything about you other than what you've posted, and those two personality disorders seem to correlate very well to the personality types I've mentioned, so I don't fully understand the difference.
Here are a couple links for you to take some personality typing tests, the enneagram one is pretty simple, the MBTI, in my opinion, is a bit more difficult, they'll tell you your types based on your answers.
http://www.enneagramquiz.com/quiz.html
http://16typequiz.com/quiz.html
Here are two parts of the forum you can look through to get more info, find others you can relate to and talk to
http://personalitycafe.com/forum/
http://personalitycafe.com/enneagram...-theory-forum/
Ok, I apologize for the long post, and I apologize that it's not what you're looking for, I know you're looking for a mental disorder type answer, but maybe these can help you understand yourself a bit better, maybe it'll make more sense than trying to place yourself in a mental disorder. If then you still don't find what you're looking for, well then at least nothing was wasted because chances are you did at least find a little something in what I gave you.
And if you do think there's a mental disorder related problem rather than a messed up personality type (and I actually love being a enneagram type 4, I love the strong emotions, so I don't see much issue, even if it does create hassle) then do as you know you should do, see a professional
Best to you,
AniveCsebure