I’m sure this is terribly painful for you. But the most important thing you said is that you do know that your daughter loves you. Although the family story seems to be that the move when the girls were young is the basis for her unhappiness, I’m not sure that is the case. She was so young at the time and problems later emerged at middle school age — a time that is tough on many kids. Like many kids, she didn’t share with you what was making her so unhappy. Like many parents, you didn’t know how to draw her out. Although it isn’t really fair, she may unconsciously resent that you didn’t seem to understand what she needed at the time and couldn’t help her. (That’s just a guess that would be explored if she were in therapy.) As she matures, she’ll come to understand that the situation was more complicated than that.
It doesn’t surprise me that she is happier in Boston. For many young people, getting away from the hometown is a way to get a new start. Further, the family story is that she was happy in Boston so she has positive associations with being there. At college, she has had the opportunity to make new friends who don’t know her as that unhappy kid who was bullied or invisible in middle and high school. She gets to be the self she wants to be.
Her disconnect from you may be painful for you but it’s also quite normal. She’s figuring out who she is. Love her. Love her a lot. Don’t put pressure on her. She comes from a loving home. Chances are she’ll come back to you as her self-esteem builds and she feels more confident in herself. Celebrate her successes. Be there if she calls in distress — not with advice so much as reassurance that you know she is smart enough to figure out what she needs to do. Have confidence that you raised her with love and from a good home.
I wish you well.