You might be able to do some things that might help her deal with her anger and sadness. One thing you can do is distract her from those moods... offer to play a game with her or watch a movie with you... Instead of posing activities as something to help her you might state it more in the tone of "would you play xxx with me?" "please watch this movie with me. I would really like it." If she thinks she is helping you she may be less likely to refuse. Even though she is becoming physical, at least she is taking it out on objects, even those she really can't hurt or hurt herself with like soft pillows and cushions.