Context: LGBT - New "relationship/friendship" (we both said we like each other but that's as far as it got) - talked every single day morning to night when not working, for 3 months.
Had an argument over messages (after a lovely weekend away together where we shared some intimacy for the first time) - argument was her doing, her ranting, completely irrational in places.
She then ignored me for 3 days even with me checking in via messages which were all ignored.
She eventually replied saying she had been unwell and would tell me when she was fully better - and disappeared again.
Today she popped back up - completely normal, full of excitement, sharing ideas for future plans such as a gig coming up in November (which she asked me to be her plus 1 to) and sending me links for a hike to go on that weekend too.
Then random normal chat all evening via message, though nothing romantic, but just sharing her day with me like usual - what she was eating, what she doing etc. Finished with "nice to catch up today xx"
I'm just so confused, honestly...how can she just pop back up like nothing at all happened? Was I discarded? Painted black and now white again?
Or maybe I have it all wrong and she doesn't have BPD at all (my friend who worked in a psychiatric hospital on the personality disorders ward is convinced she does though...)
Maybe she just wants to be friends now...I can't tell...(more confusing with LGBT relationships)
Any thoughts?!

Mango, focus on you and less on her. Quit worrying about it. Things will play out how they will play out. You are causing yourself way too much anxiety and stress for no damn good reason. Stop it...seriously.
You are over-analyzing way too much. Focus on YOU, Do YOU, and let things take their course. Essentially, lead by example and show yourself more love and attention and let everything else follow. This is where you need to train your mind to be indifferent in the sense you are happy if you do end up being friends, you are happy if you get in a relationship, and you are also perfectly happy if nothing comes of it. Put yourself into a win-win situation instead of allowing your mind to dip into the negative side coming from a place of desperation and weakness...meaning your mind goes to win-loss scenarios. You can only control you so that is all you should be worried about and focusing on.
Additionally, that mentality makes you more attractive in general and gives off a more confident, positive energy and becomes infectious. I am pretty sure that is what you want right?
Hey how about this...what do you want for you? What do you want to do? What goals? Etc...use your mental energy on that instead of driving crazy about too many variables to which you really have no influence or control over. Sound like a good plan to you?
Cheers and Best Wishes!
-SC-