No MOM, it's a control thing.
Unfortunately, she's got your number. What order of child is she? Also, is she in Kindergarten? If so, does she act out like this with anyone else or just you? How about Dad?
I had some issues with my 5year old boy it started aabout the second week of kindergarten. My advice is this: On the spot immediate action needs to be taken, now. Once my guy realized I was serious, it stopped. I'm not a tyrant, but I won't let my boys call the shots. My husband was on board with me and let me take the lead, since he's working and I'm at home. My house, my rules.
We all try to make sure our children understand our actions, but it's a two way street and you are the parent. She needs to be put on the spot and made (nicely) to explain herself and her actions.
Yeah, I know, she's 5. Okay, a special time out spot is going to be needed. Try the bathroom, it's really boring in there.
As soon as she begins, stop her. Address her like a stranger child, she won't expect it. Don't use her name. Say something like this- "excuse me little girl, this is my home and this is not how my children are allowed to behave. why do you think it's okay to act like this"
She'll look at you like you're nuts.
Now you have her attention.
Now you're in control.
Set down some rules- in writing, with a positive and negative column. So many in either will result in a ...
Make sure everyone follows them everyday. No exceptions.
Start real action. Start by taking away or suspending the things she likes to do. Organize her day to your schedule and what's best for you. Once she sees her actions and reactions are a negative, she will have to turn it around or loose out.
I know this sounds stupid but is she getting enough sleep?
Good luck-kate