This might be a very naive post, but I am concerned about my daughter, who is recently becoming increasingly grumpy, sour and negative. It's not ALL the time, but more and more her responses to me, her mother and brother have such a huffy and gloomy tone. I assume this is not uncommon preteen behaviour, but I guess I would just like to hear from people who are going through a similar thing (so I feel less like I have made some unique and irreversible fuckup) and also from people who have found successful ways of dealing with it and helping their child connect with their more sunny side.
Google 'Pre-teen girls Angst.' There are several sites that will perhaps tell you what stage of development your Pre teen daughter is about to embark upon. Also look at bullying at school just in case. Meanwhile try and keep calm in the face of their horrible selfishness as it is agony being a pre- teen girl. Eventually it passes. Mine came back , from where ever the nice girls had gone, around 17. It was horrible when I knew they felt ashamed of me. Now they love going out shopping with me and my purse. Believe me it will all blow over, just be patient. Read some books on Puberty it will help you understand. I feel sorry for girls now, what with FB and the focus on designer gear and too much knowledge about sex. Poor things it is no wonder they are grumpy.