Re: 3 year old discipline and sleep problems
Three year olds are very oppositional.
Only say what you mean, and mean what you say. Think before saying "no" or "Eat", or whatever. Is it really important? If not, don't get into the power struggle with her, because you will just lose.
Three year olds love and want choices. "Do you want mommy to open the door? Or do you want to do it?" "Do you want the red pants? Or the yellow pants?"
If it's a deal breaker, stick to your guns no matter what. Eventually, she will learn that you are serious about this issue, but, are willing to negotiate all other issues.
Meltdowns are normal too. They have so much information going in, and not as much coming out, that it's overwhelming. So, they just meltdown. Patiently wait it out without coddling, and try to chill out yourself for a while.
I was never into co-sleeping, so I have no advice on that subject.