Could I have led her to commit suicide? Was I uncaring? Let me know if any similar experiences... . to this day she tells me I drove her to it.
To me it screams of being an act of manipulation and is very common for someone with BPD when they feel like that's all they have left to trump you with. My exwBPD did it in a very similar way but she also cut her wrist (albeit not enough to do any real harm) but it was enough to get her admitted to the psych ward at the hospital for a week.
You tried to get her help. How is that uncaring? By her continuing to tell you that you drove her to it is more manipulation on her part. You did the right thing by breaking it off with her. It's not going to get any better. Be thankful you didn't marry her. I spent 19 years in emotional prison (marriage) with mine. I'll struggle every day of my life from here on out.
Good luck.