Hi Elyria
Learning about BPD can be quite liberating and validating yet also very overwhelming. I have an undiagnosed BPD mother too and found out the same way you did. I started searching on the internet, I don't remember exactly what I typed but it was something like "my mother sabotages everything I do" or "my mother sabotages/undermines me every step I take".
Having a support network can be invaluable and I am glad you have found your counselor so helpful.
I am sorry you had this recent unpleasant experience with your mother. Her behavior has more to do with her than it does with you, yet even when you know this it is still difficult of course. It sounds like she might be engaged in the BPD behavior known as 'projection':
In general, emotionally healthy people base their perceptions on facts. Projection is basing your perception of reality on feelings.
Projection is a defense mechanism, operating unconsciously, in which what is emotionally unacceptable in the self is unconsciously rejected and attributed (projected) to others. Projection is denying one's own unpleasant traits, behaviors, or feelings by attributing them, often in an accusing way, to someone else.
Commonly the projection is an exaggeration of something that has a basis in reality. For example, the borderline may accuse you of "hating" them when you just feel irritated. Sometimes the projection may come entirely from their imagination: for example, they accuse you of flirting with when you were just asking for directions to the shoe department. ~ Randi Kreger
Some adults who enter into relationships with borderlines feel brainwashed by the BP's accusations and criticisms. The techniques of brainwashing are simple: isolate the victim, expose them to inconsistent messages, mix with sleep deprivation, add some form of abuse, get the person to doubt what they know and feel, keep them on their toes, wear them down, and stir well. ~ Elyce M. Benham, M.S.
Do you feel like any of this applies to your mother's behavior? You can read more about projection here:
BPD BEHAVIORS: ProjectionI think it is very positive that you are now educating yourself about this disorder and are reaching out for support here

You indeed are not alone, many of our members know how incredibly tough it can be having a parent with BPD and will be able to relate to you.
Take care and welcome to bpdfamily