My 5 year old daughter is showing signs of jealousy over me and my husband's?

relationship, lately everything is about "Daddy loving Mommy more than her" Also I am 7 1/2 months pregnant so I know this is a big new change for her. Lately I've been super tired and Daddy has been having to take care of me alot more and we havent been able to do much on the weekends because I cant take the heat.(we live in Florida) Everything since I got pregnant has been about our daughter's "last this and that as an only child" for instance a 4 day disney trip, and for her birthday we are taking her to Dolphin Cove to swim with the Dolphins before baby Kevin comes. So we've been focusing on everything being happy memories of us before the baby....How can we explain and really SHOW her she is and will ALWAYS be our precious little girl. The new baby is a boy and he is due Sept 2nd. Her Birthday is Aug 11th. So this is coming so fast and we just want her to NOT feel like she doesnt have a place or that she isnt a vital part of our family!!! How do we explain that we are a family and we all Love eachother equally! Because her attitude and how she displays anger or frustration has been coming out in the form of NOT LISTENING or doing the opposite of what we say lately....