Hi FoxC,
Welcome to the boards

,
Your story sounds similar to many of ours. We have a lot of workshops on the right side of the page to help us learn more about our pwBPD, our relationship dynamics, and some tools to better communicate with our pwBPD. Sadly, when someone disappears and wants to be left alone, there isn't much we can do to stop them from doing that. During those times, it's important to let them know that you care for them and that you are available for them if needed, but most of the time they just need their space.
You mentioned that you felt like you were possibly rescuing a little too much. Here is a link to one of our workshops on "Are you supporting or enabling?"
https://bpdfamily.com/message_board/index.php?topic=95263.0