I strongly agree with the advice to make sure she gets more sleep. Establish a very consistent, early bedtime routine that is fun, relaxing and loving. Do it the same way, the same time every night for at least two weeks (it won't happen overnight). Make sure she is getting a very solid 2-3 nap every afternoon too. Sleep deprivation causes so many problems in kids.
Also, make sure you are getting her out of the house for physical activity and fresh air in the mornings and that she is stimulated when she is inside (no to very little tv). Music, art, banging on pots, rolling balls, reading books, etc. A bored child is an unhappy and challenging child.
And do try to readjust how you see her. No 2 year old is rotten. I know how frustrating little ones can be (have two of my own and have taken care of countless others) but they are so very sensitive to our moods. If you are cheerful and loving and engaged, she will calm down. If you are exhausted and frustrated, she will feel that too.
Take a deep breath, look at how you can adjust your schedule and her environment. Remember that, as her parent, you are responsible for setting her up for success and for loving her more than anyone else. When you feel like yelling at her, take a deep breath and hug her instead. Try to figure out what the problem is and how you can work with her to feel better.
Good luck - it really is hard work!
B.
Momma to a very spirited 19 month old and 4 year old