Another voice agreeing that middle school is the worst. Our D broke up with a group of cool girls in 8th grade. I didn’t know until one day, out of the blue, I saw her sitting with a different group of kids at a different lunch table. I’ll never know the details, but it was a big deal and emotionally difficult for her.
Some of the girls from 8th grade also went on to the same small private high school. Our D remained cautious around these girls after her experience in middle school, but tried to take a neutral stance, aka tried to be friendly/neutral with everyone & not get boxed in to one group.
By senior year, she and one of the cool girls from 8th grade had become actual friends! People change. Things change. It’s a tough, vulnerable age.
If your D is open to it, a good therapist who specializes in that age group can be worth every penny.