Help me understand my 6yo dd..

[jenniferalisonphillipasue]

My 6 year old dd is driving me to distraction at the moment. She is a really lovely girl and I am incredibly proud that she is my daughter. She does however exhibit some slightly odd behaviours which I am finding hard to manage at the moment.
The biggest thing currently is that she keeps making noises. It started with whistling and is now clicking her tongue or other similar mouth noises. It is really bloody annoying. I know she is not doing it on purpose and I feel bad for asking her to stop all the time but I can't bare it. I think it is an outlet for her energy. She finds it hard to sit still (not to concentrate but to keep things still whilst doing an activity) and will always be fidgeting at story time etc. She does however seem to absorb all the information and is very bright.
She is very literal, for example, if you ask her to get a pen from the desk and it is not directly on the desk I.e on top of something else on the desk she won't think to bring it because it is not "on" the desk. She does not have any common sense at all and can't get her shoes on the right feet and is constantly putting clothes on inside out/the wrong way round.
She has an obsession with clothes at the moment but is constantly going through her drawers and getting things out that have been washed and ironed and leaving them in a crumpled heap on the floor. I got really cross tonight because I am fed up of it but she just can't seem to understand why I am upset. When I said if I found them lying around on the floor again I would put them in the bin she got upset but only because she doesn't (understandably) want her clothes binned. She can't seem to grasp that if she doesn't do it I won't have to put them in the bin. It just doesn't seem to occur to her.
She also has a bit of a lack of social awareness -says things at inappropriate times, can't read people's reactions etc.
She is no 2 of 4 and I know that her behaviour is "different" to others. This is not in itself a problem but I just want to understand how best to deal with it rather than getting frustrated with her.
Sorry for the long post.

I hope I am not the first person to suggest this but it sound like autism. The echolalia (making noises), literal thinking, difficulty with social interaction / interpretation, fidgetiness and obsessions are all classic signs.

I'm sorry if this comes across as cold. It isn't meant to. Please feel free to pm if you would rather this discussion wasn't public.

As a child I had like vocal tics, I was an anxious child, big family, my brothers were very teasing and my confidence was low.
I outgrew it, but looking back I also wasn't very socially aware and just really shy and awkward in general. I think mostly a confidence thing for me.
Usually if I relate to a post I can think of a child like that I have looked after or a quality in my own dc, but reading yours I thought my Mum could of written some of those things about me.

Not cold at all. It has occurred to me but whilst she certainly exhibits some traits, in other ways she is able to function perfectly fine. She seems to be able to develop friendships normally, is popular at school and enjoys the company of other children. She does not have any problem learning although she likes learning within the rules and is mathematically orientated. She was an early talker and had no language delay. She has good motor skills and is very physically able.
In some ways she is quite similar to me but her brain definitely works differently to mine so I do find it her frustrating sometimes which makes me snappy with her.

Thanks Rabbit. She is a confident child which in part stems from her lack of awareness. In some ways I think this is good as she is pretty much oblivious to some of the complex relationships of girls so playground politics don't affect her. She is however at a very small school and is sheltered from this to a certain extent. I am a little worried as to how she will be at secondary when that sort of stuff becomes more important.