M.M.
Ask her why she hates school. Ask her what would make it better. Does she have any real friends in this class? Does she eat lunch with anyone? Is the male teacher overbearing? Can last year's teacher come in and say Hi one day next week?
I assume she will get back to her normal self once this school year is in full swing. Everything is new, new kids, new rules, new teacher, maybe a couple new teachers. Give her time.