My son went through this. i was mortified hed thrash, scream throw himself all over and i felt totally useless. i spoke to my health visitor and she asked if we had anything stressful going on, i said we were currently in the process of moving house. she also asked if he had a good imagination, he does. she said what was likely to be happening was that he wasnt switching off from his imagination and was dealing with the stress of moving house. he was 3 at the time. she said that he has no idea what he is doing or any recolection the next day. and its harder for the parent to deal with than the child. she said that its best not to wake them when its happening just to soothe them and reassure them with words ensuring their safety especially if she is banging her head, my son hit his head off the wood at the bottom of his bed and i was distraught. it is a really hard and tiring time, and she will eventually grow out of it. try and see if theres anything that could be causing her any stress, with a child it could be something so small. just carry on being a good mammy and be there for her and remember it will stop. by the way im also a nursery nurse of 12 yrs and the things that can play on a childs mind really can be the smallest thing but in their eyes it can be so big. hope ive helped