S.,
Been there, done that. I was a stay at home mom for 8 years before going back to work. I have 4 kids ranging in age from 10 to 3. My daughter, who is now 5, was like that from the time she was 2 until she hit about 4 1/2. I thought I was going to lose my mind! I feel ya! What worked for us was giving her chores to do. We sat Katie down and explained to her that we needed her help to take care of the family. She liked that idea. So, we made a list. While mommy is doing this, I need you to.... (I'll list some suggestions)
1. while Mommy is downstairs doing laundry, I need you to entertain your brother and read him this book. (even though she couldnt' read, she told him the story by the pictures.)
2. While we are in the car, Mommy needs you to watch out for X (a red car, a blue car, a sign with the letter A in it etc...)
3. Mommy needs you to help make dinner. She can tear up lettuce, measure out grated cheese. count baby tomatoes. Put silverware on the table, count out and arrange napkins etc...
We found most of what worked was distraction, and also, she needed to feel she was in control of something. (you know how us girls are with that! lol)
The other thing we realized was that she had trained me and knew if she cried hard enough, I woould give in. That is why she never pulled that with Dad. He didn't give in.
So, when she started to get out of control, I had two actions to pursue. 1. tell her I could not help her if she was crying and I couldn't understand her. 2. Was to put her either on the stairs, or in the other room and let her know she could have some time to pull herself together, then we could discuss what was really wrong and what she wanted. (that didn't mean she was going to get it, but it helped her to talk about it.)
If that didn't work, then I told her, this is the way it is, I understand you don't like it, but X has to get done. And put her in a safe place, ie: on the stairs, in her room, on the couch. and walk away. Tell her you will talk when she has calmed herself and whatever you do, don't give in!!! (I know that is so hard when your baby is freaking out.) But crying really won't hurt her. It's much more painful to you and she knows it. (a very hard lesson for me)
And trust me, I'm NOT an advocate of "let them cry it out." But sometimes, they are so emotionally "wrung out" it's all they can do.
this is just our experience, and by no means advice. Just what worked for us. Good luck, I know how you feel. Our house has been much more peaceful since we got her under control. She still has her moments, but she's still little and it's hard to controll emotions that you can't identify, for anyone, much less a 5 year old in a house full of boys!! lol