My 5 years old daughter is very challenging

Hello. I'm from France. My daughter is almost 5 and for the past 2 or 3 months she has been very challenging, I feel totally lost, I don't know how to react and my husband and I have been arguing more more about the best way to handle her. She's an only child and we spend a lot of quality time with her, specially me who doesn't work at the moment. She can be very agitated, often clowning and doing silly things especially when i'm tired,  or when we meet one of her friends outside.  At home, everything is a battle, she never wants to cooperate, she says all the time she wants to be an adult and do what she wants! She acts like a little madam, talks back to me, really provoking me. It feels like more I give her attention, more challenging she becomes! I try everything, more i ground her, more she acts like she doesn't care (she even says it!!) , sometimes she has tantrums, she spit on the floor or try to hit me or herself (not often though). I read books about authority but I don't know which way to go with her. I just don't understand her! And I feel so guilty all the time...What should I do??

[Kevin Kennedy, Ph.D.]

You will find a valuable resource in Lynn Clark's SOS Help for Parents. This is a practical, straightforward behavior management manual and will likely be a great help to you.