Refusal to go to school in initial days of schooling is normal, but in middle of term can be a serious issue. Anger outburst on mention of school along with refusal to talk regarding friends needs an detailed evaluation. Arrange for a child psychologists who can do play therapy, or talk to the school counselor. Many times the cause may be an annoying teacher or a fight with classmates but sometimes there may be a abuse so Kindly treat it as a urgent matter.
All the very best