What are you looking for folks here to do? You’ve already noted that you don’t like change and MS is obviously a change that comes with all the things you noted: More students, students from different schools, changing classes, lockers, bigger building, phones, etc.
Take a deep breath and just accept that all these changes will occur and it happens every year for tons of students. MS are adept at welcoming in 6th graders and it’s really just the next year of school and development.