How can I approach her without losing my cool?
For me that depends how distraught and fragile I am feeling because of her. Sometimes I have to be NC for my own well-being. This is to protect both of us. Other times I feel quite strong, and can manage to set boundaries as well as using other tools such as SET and validating questions, and keep my humour and wits and objectivity about me.
I have never ventured far from home. Mom always said something awful would happen if I did. I am currently just trying to deal with her constant commenting of how I will be abandoning her, how I'll get lost, wont survive without her etc.
What I have learned (from ignorance, the hard way) is that if we try to assure a pwBPD that "they will be fine" once we have left, they find that really invalidating. It escalates. One time we were leaving for 3 weeks on a family vacation out of country (our adult GC offered to tell her),and my mom reacted by saying many things, one of them being "she could die while we were gone". It got worse and worse as our departure approached. Thankfully she had friends who stepped up to fill her void once we were gone. I can just imagine how this is going for you right now, since it's a move, and not a short-term vacation. The closer your departure gets, the harder it is likely to be. I would scheme a way to avoid the "goodbye" on the last day. Say it the day before if that is possible in any way. If possible, try to have someone with you when you say that final good-bye.
SET and validating questions is all I can think of to offer as suggestions. They will be the best tools to cool her emotional temperature, and validate her.
However bad it gets, feel positive and proud that you are moving on with your life and a new opportunity. Good for you!

It's the
normal thing to do. What you will probably encounter before you leave is anything but (normal). She's going to FOGFOGFOG you. I feel for you Naty, I really do. Find time to look after yourself - however you do most like to do that. As impossible as it seems while preparing for a move, we want you to take care of yourself now, so that you are in a "good place" to start your new job and life when you get there!
So happy for you! Congratulations!
