Girlfriend distancing

20F, 20M. Hello, I've been in a relationship for 1.5 years, and while we've had our ups and downs, things took a turn recently. Over the past month, my girlfriend has been distancing herself from me. We live apart, and in the last three weeks, I've been organizing fewer sleepovers as I'm in the process of moving to a place where I intend to live with her. I thought she was excited about this change, but since we visited the new place about two weeks ago, she's expressed second thoughts and has been quite negative about the idea. She tends to be more pessimistic than I'm used to, which I've come to accept as part of her personality. She also experiences mood swings and often shows her affection differently from one day to the next. She self-diagnosed herself with BPD, or at least that's what her high school psychologist suggested. Today, she told me she's losing interest in being emotionally close to me. Over the past month, her texting has become sluggish, and she's fallen out of our usual routines (like good morning texts and saying "I love you"). I might be overreacting at this point. I’m just not ready to let her go; she’s one of my first serious relationships, and I always envisioned her by my side. I'm hopeful that things might improve when she spends some nights at the new place, hopefully next week. I'm looking for general advice on how someone in my situation should approach this.