hello and welcome !!
I can understand it feels impossible to process all of the feelings that comes with a realationship with bpd.
it is normal to to feel things with a post break but sometimes with bpd those things are intensified because of the dissociation and what we have perceived to what the personal with bpd and the false reality that the amazing feelings at the start is mirror imaging. let's face it everyone person likes to feel valued.
I think you will need time to process your feelings and work with your therapist.
It it understandable to feel hurt/anger/ even confused by the behaviour those all these things unfortunately they have a disorder and usually very unaware of their maladaptive behaviours.
I think you could try to focus on your self and start to heal I would suggest finding some hobbies and work through your emotions maybe with counselling ad they would help you work through this.
spend time with family and friends.
Many of us on here feel the need to look after that person because we care about them even if we actually burn ourselves out.
The important thing is to remember to care for your self. and be kind to your self any post break up is still grieving and that is alone it's own process and has 7 stages everyone will go through.
When I split with my exbpd, I felt very lost and unfortunately he did nearly convince me that I wasn't OK. i became a caretaker over night without realising it, i also didnt have great boundaries at the start which didnt help the realationship either. not every person with bpd will be the same but most will dissociate/ split black/ trianglate it's a coping mechanism for their own feelings.
You aren't responsible for her actions or how it ended or actually getting closure post break up. as many of us there isn't always a logical reason behind it for closure to happen. I walked on eggshells for a long time post break up.
I would also try to think:
was you really happy that time of your realationship?
if you could see your self with them in 5 years do you think the picture would look how you see it or a very different picture of what you would like?
I would look at your own attachment style too.
sometimes we develop trauma bonding during a disordered realationship.
I've been out of a realationship with my exbpd coming up 3 years it took me a while to heal but I got there and so can you, I'm now seeing someone who it's not all fireworks and was slow to dating that's because I had anxiety towards meeting anyone but it's nice to be out of the fog and happy.
on the tools page there is some lessons you could look at to help you process what she may of experienced and how to work and some tools on the detaching thread there is many posts that can be quite insightful.
try to live in the present not the passed of what happened and how could they do that because trying to find answers you might not even get.
I do hope you start to heal and find your self again, every cloud will have a silver lining.
Take care
Kaytee