Is it just me as a mom..?

So im currently 27 weeks pregnant with baby #2 and i have a 5 year old daughter about to turn 6, shes always wanted a sibling and does great with her baby cousins and other kids. I've tried to include her in my pregnancy in every way i can like scheduling my appointments after her school is over so she can come and letting her pick things for the baby ect. She's never shown any jealousy about a new baby shes more over the moon excited and has to kiss my belly every second she can but now that im farther along shes been acting out at home , im actually crying in my room right now because i don't know whats gotten into her and i feel guilty. She knows better and gets disciplined but lately shes just been really pushing it i sit her down and talk to her but for example she knows about her bed time routine and never had a issue but all of a sudden she just started to play with her toys i told her she can do that tomorrow right now its bed time and just went onto a screaming tantrum at the moment her dad has been working night shifts so i don't know if its affecting her now or i feel like i can't handle it... and i try to do my best but its now eating me up. Im also worried my stress will affect the baby. I know my daughter and this is not like her