I need some help...

[HelpinOthersHelps]

My friend's boyfriend has a little sister. She's about eight years old and she is usually an outgoing, talkative kid. Like normal at that age I suppose. But today, she contacted me [my friend] and told me that the little girl has done a complete 180 degree turn around.

She doesn't talk much, she keeps asking questions suchs as: "Can I shut this?" "Is it okay for me to put this here?" but then she goes right back to normal not that long after. Also, she acts like a germaphobe now, which wasn't normal before. She cannot remember what she did in school, she told her mother that she was thinking that she hated her, but when her mother told her what she was thinking, it made the little girl upset.

Then, she was at a pool party and a friend of her's help laughing while in the pool, and she told her to stop since she thought that she would drown, but then she kept making her laugh to see what would happen.

Also, her older brother took her to the mall and gave her some money so she could get something from the gumball machine, but she replied with "I can't get the candy now because I touched the money and my hands are dirty now." Then later they asked her what she did in school [again] and she changed the topic to a movie on Disney Channel and then said that her brother never asked her about shool.

It also seems as though she is aware of what she is doing, since she told her mom that "I don't want you to think I hate you or anything and I didn't mean to think it, but I thought I hated you."

It seems as though she knows that is going on, but at the same time, no one knows what is wrong with her. Can someone please give me an answer? She's just a little kid and her brother is really worried about her.