I'll start off by saying in nearly 35 weeks pregnant and know I've been a hormone mess over the most random things so this could be me making a mountain out of a mole hill.
We're a blending family DP has 2 DC and I have 1. We've had a rocky path but worked hard on getting through it all, we've had his DC 85% of the time since March and my DC 100%.
The problem is over the last few months all of the DC seem to have just completely decided to ignore me, don't listen to a word I say or ask, don't do basic things their expected to do unless their told my DP. For example we've always had a rule dirty washing straight in the wash basket if it isn't there it doesn't get washed but the last few months no one listens, dirty pants left anywhere and everywhere, clothes, favorite PJs but then when they want something I get the attitude of it's not been washed 
I have to repeat myself a million times for the basics, brush your teeth a million times, tidy your toys away (this one never ever gets done), I can literally ask one of them to do something they say yes and then turn around and do something different.
DP pulls them up everytime and there's consequences for ignoring me but it doesn't seem to have any effect and they still ignore me. They all want me to play games, do fun stuff, buy them things but that seems to be all I'm good for.
I did wonder if it could be a jealously issue with the new baby coming but they are all so excited, have been involved in picking things out, suggesting names and tell everyone their going to have a baby sibling.
I'm at a loss. I feel like we need solid rules and consequences but feel so irrational I don't know if IBU anyway so I'll leave it to MN jury to decide.