7 year old behaviour

[ilmab2202]

my 7 year old refuses to talk to me about any problems/ issues she may have and can then act out in various ways. she appears to have been worse since school as began & this morning said she was feeling ill but i sent her in anyway. on her first day back (and her sisters 1st day of school) she threw a massive strop all the way to school and we almost had to lift her into school - straight way i had left she settled down and was fine. She refuses to go to any kids parties with the excuse of "i dont do parties" or its too loud, she used to love parties in the past - but now will not go. if she has friends around the house she ends up bawling and crying and not speaking to anyone - this has happened everytime we have been out with other children or they have been here at home. She has acted out over the summer quite a lot and has been very difficult to deal with. i am getting extremely frustrated and irriated and not being the best mum in all of this. i want to help her but she will not let me enter into her world. it seems that there is a massive gulf between us and i dont know how to reach her. i seem to go through every emotion at present with her and at my wits end. She wants to do something every day (after schoool and weekends) but when we do she acts out. She has just moved up to juniors but has been behaving like this in infants too. She pulls away from her friends at school and often plays by herself - she is doing this more and more often. Does anyone have any advice ?