((( HUGS ))) - I am so sorry that your big sister is being so mean to you right now..... and that you mom was not supportive - and while siblings do have to learned to get along together I feel that a parents should always step in when physical hitting is involved.

And while "as a parent" I do not condone hitting - I have to ask (as a once smaller younger sister) have you ever hit your sister back as to show her that you are not afraid or to put her in her place?