Secondary school is a bit rubbish for friendships, I've found. Both my teen girls struggled to really find their people up to year 11, hung out with this group and that, but never truly in the centre of it or having certainty about them. That ok, school isn't all about friendships, encourage your dd to see the point of school as doing well in her subjects, exams, taking part in extra-curricular, make sure her life is interesting out of school (coffee together, events, holidays) and as a family.
Both mine have gone on to find much better friends after age 16 at college/6th form, they seem to know now who they will gel with and be able to keep in groups, initiate going out and talk more, so it's not necessarily a disaster if it hasn't all happened at secondary. I was the same, and I have a lot of friends as an adult, not so many as a child.
Of course there may be something underlying all this, but the main message for me would be the opposite of what people are saying here: you are just fine, you are a great, lovely, friendly interesting person and your time will come. It's hard to practice social skills in the average comp, it gets much better as you age.