As you discovered, it is usually not a good idea to tell someone you think they have BPD. Many of our members have made the same mistake
Been there done that. They can take offense or they know already and its like the "how's the weather up there" joke for tall people, they've heard it (or variants) a thousand times before its not even funny anymore.
I have come to realize that my anxiety and stress are primarily in relation to my interactions with my partner. She is what I affectionately term "a snap show". I cannot say anything without her jumping on me, defending her position (to the death), and/ or attacking me.
My dad would do that a few years back (we suspect BPD but never had much evidence besides anger outbursts), it was often triggered by something bad happening at work but he would lash out at home.
Takes some serious skill to navigate through that and I don't want to risk giving bad advice because its a delicate issue so just know it is possible, its hard, you need a lot of resilience on your part, things often get worse before they get better, but it is possible.
As for the anxiety, I had panic attacks a few years back, helped me tremendously just to be aware of the early signs, just knowing it was anxiety allowed me to focus and experience it without escalating it (worrying about the fact that I'm worried about stuff, that sort of thing) usually allows me to get through it. Haven't had a major event in a while now so yeah.
Can you tell us more about your relationship? It will make it easier to guide and support you
I agree with Harri.
