The Rocking of Her World

Ok, we're living w/ the sleep thing. That's ok, we'll make it.  Right now, the hardest part is the adjustment w/ my 8 year old.  Alex has always been a strong willed one (a bit of an understatement), but we're seeing a whole new level on the stubborn scale.  Before I rant about my daughter, I must tell you that I love her so much, and she's an amazing little girl.  She's just experiencing the "rocking of her world" that I predicted would occur when Jesse came home.
It seems that once a week since the summer began, I've called Steve to cry and vent about my horrible day w/ Alex.  She just doesn't listen, and I'll discipline her for one thing, and she turns around and does something else crazy.  She's now in her room for an hour after already losing television, computer, and DS privileges for the day.  UGH.  Do I lose my temper?  Yes, yes, I do after the fifth round; I end up yelling.  Sorry.
Do I think it's a jealousy thing?  Probably.  Is it that she's so used to the world revolving around her?  Yes.  It is what it is.  Kids all over the world have to go through this.  So, I just gotta share today's journey:
1. She thew a fit this morning because she wasn't allowed to go to the fair w/ her dad who is WORKING on the Habitat house there.  Ok.
2.  She's angry that there's "nothing for her to eat for breakfast," and complains in the most "privileged" way possible while staring at a loaf of bread, peanut butter, milk, english muffins, toaster egg thingies, and cereal.
3.  She runs at mock speed w/ her little brother in the cart at Meijer at 9:30 this morning.  She does this three times, which each time she was told not to do this for the many reasons you could imagine, especially that this is the prime time for the elderly to go shopping; not good.  The third time resulted in her losing access to tv, etc. for the rest of the day.
4.  We get home, I put Jesse down to play in his little play area while I carry in the tons of groceries, she picks him up w/out permission and when she feels like it, puts him down so he tips over on his toys.
5.  Then we move to chores.  Each 5 minute chore starts & ends w/ "Do I have to do this?" & "I don't want to do this anymore."
6.  The straw that broke my back was when she yelled at me while I was on the phone & when I got off the phone w/ grandma because I didn't tell grandma something.  This resulted being sent to her room for a long while.
For me, this is tougher than lack of sleep.  She gets tons of positive attention & praise; trust me, I'm vigilant about looking for every minute, positive thing she does.  Oh well.  I'm ready for school to start like yesterday .  Thanks for letting me vent.  Much love!