Hey KtotheK,
You've had a stumble on your path ... .& your reaching up for a hand to help ... .so let me be one of the first to hold mine out and pull you up ... .dust you off and lets get you started on your journey again ... .this time lets try a different path shall we?
First ... .YOU should not care what others thing of you & this included your pwBPD. So it really makes NO difference what the meaning was behind the text right?
I had various view points ... .just feeling guilty and bad and reaching out. Possibly feeling lonely ... .possibly setting up for a recycleMy question if your intent is to remove yourself from the flying monkey's of your EXpwBPD why haven't you blocked them on your phone/FB/social media altogether? Better yet why haven't you gone to your carrier & asked for a new number. You should be able to do that right online.
Imagine for a second if you had done that ... .REALLY think about this for a few moments ... .get your head wrapped around it. If you had done that your EXpwBPD wouldn't have been able to reach out & touch you via a text, etc. And by NOT being able to reach out to you ... .you wouldn't currently being feeling ... .what did you say ... .oh yeah ... .
"I feel sick, scared, anxious" But now you're inside your flat dealing with her flying monkey's she let fly to cause YOU chaos, pain, hurt.  :)o NOT try to use logic as to why they texted you because their Very Serious Cluster B Mental Illness doesn't & will NEVER make sense to a NON because the two are NOT connected.
SOO ... .instead of worrying/thinking/obsessing/wondering about her causing you to feel sick, scared, or anxious ... .YOU should be thinking about taking BETTER care of YOU~! YOU can NOT do that if you're obsessing about your EXpwBPD right?  :)o NOT let her behavior be a concern of YOURS.
Instead ... .you should be going for a run/walk/gym to burn off some stress ... .you should go get that slice of cake for breakfast with your tea in the morning.

You should be making plans with your mates to go see a comedy show this weekend or go to a sport event this weekend. You should make the appointment with your therapist to continue to work on yourself and why you are the rescuer/perfectionist/codependent that you are? You should be enjoying a sunrise with a cup of tea/Monster/beverage of choice in the morning. YOU should be working on YOU.
Let her flying monkey's fly right over the top of you ... .Let the Crazy Train leave the station without you buying a ticket ... .Let all that other crap go~! Just let it go ... .
In answer to your last question ... ."What should I think?" YOU should THINK about how BETTER to take of YOURSELF ... .thats what you should be thinking ... .
I'm not yelling at you, I would NEVER do that ... .just pointing out some things that you might not see because you have BPD blinders on right now ... .I'm asking you questions & responding to yours ... .
Like ... .if you're on the ":)etaching" board ... .why is it that you haven't blocked her from all your social media? Jus asking. So now what are you going to do on your journey ... .sit back down & do nothing? Continue down the current path & see how that continues to work out for you? Or do you choose a different path and see where that leads you too?
Take a deep breath KtotheK ... .it's going to get better ... .it REALLY does You're just having a moment ... .the moment is now past ... .here's me patting you on the butt ... .Get walking KtotheK~!
J