Any Suggestions?

Jealousy is a major issue here - but then again so is how you are handling her.

You are letting a 3 year old walk all over you. You have to show her who is the parent and who is the child. Every time she misbehaves - take a toy from her, punish her, take her tv privledges away, don’t let her come out of her room, put her in the corner in a chair, do something to punish her. EVERY TIME. You have to be consistant in order for this to work. Even if you are not at home -she needs a punishment.

That being said - when she does something nice or good - reward her. Buy her a small toy, a treat, praise her with your words, etc. She needs to know that doing good is what mommy wants and that she has to behave to be rewarded.

I would say you need to be the parent, as much as it may crush you to do this, but if she does something wrong you need to keep your calm, give her the time out and get to her level and talk to her in a calm voice, (where is she learning this behavior) sorry but you do have to look at where she is picking it up from, I am sure your day is very active and stressful, but you can’t allow the kids to see that, you need to be in charge at all times, just think what she will be doing to you in a couple of years if she does not respect you now. She may scream her head off but stick with the time out and don’t let her up until her time is up, and everytime she gets up add another minute to her time out, ASk her if she knows why she got a time out, talk to her about it.

You need to punish her more. I think she is jealous of her brother. Say she draws you a picture or does something good, give her full attention towards it otherwise she’ll just get upset and feel like you don’t care anymore when you obviously do. Also get help from your family. You might not be able to deal with this alone.