I gave birth a week ago to my second daughter and I have one dd who turned 2 a few days before. I had expected her to be a bit jelous of the new baby but she had exceeded my expections! She has been wonderful all week,helping me and I don't even think we have had any tantrums this week. Is this the calm before the storm? 
I am just intrigued to know when your new sibling arrived if the jelousy started straight away or after a few weeks/months?