Question for my daughter

I have a 6 year old girl turns 7 on september 10 my question is my wife was diagnosed with cyclothymeia(probaly didnt spell it right) and her mom has some problems that was never checked it also the grand mother, well my question is my daughter doesnt obey ever, she tries to be helpful and then she is very mean on a drop of a coin, she has very few friends in school she has teachers tell her not to talk when they are talking and she annoys the children around her in school.  She is extrememly hyper.  She also does things she knows she cant but doesnt care, for instance she will go outside in the middle of the night to go play.  twice now we had strangers take her home.  We dont know what to do for her everyone says she is too young to know.  I understand the saying kids will be kids i am from a family of 6 and my wifes family is 5.  We have 4 kids total and dont see anything in the others.  My daughter acts if she is depressed, angry, hyper.  My wife told me that she grew up very similar to the way of our daughter that she also remember the troubles in school and the not caring, she felt as she didnt belong anywhere.  Our daughter will come home with her head down saying no one wants to be her friend and we dont want her to experience rejection especially at her age.  Is there something you can tell me that we can do or have her checked for?? Thankyou