Hi Lonelytraveller,

It sounds like you are dealing with some big changes right now. People with BPD have a hard time with these types of transitions- moving on, moving out... . and so they often react very intensely. Have you read the book, "I hate you. Don't Leave Me"? Well the title says a lot even if you haven't read the book.
I see from your other post you have a serious BF and your S is angry about that as well as the moving in with him.
Just wanted to ask a few more questions:
Are your parents supportive of your move and are they also still living at home with you?
Do you have other siblings?
Is she an older or younger sister?
Having a sister act this way is very confusing I know.
I would suggest you pick this book
Essential Family Guide up this week to help you learn some strategies to make your move go easier than it has so far.
There are many here who can offer you advice and wisdom as well for improving your relationship with your sister while also helping you gain your independence from her by learning how to set and maintain healthy boundaries.
Looking forward to hearing more about you and your family.
Yours,
mamachelle