Oh gorgeous lady firstly massive . Your girls could be feeling unsure/out of sorts because of bub arriving and what is going to happen and all the changes coming all on top of being exhausted from being so busy. With both of my DS's my kids got all out of sorts, whinging, clingy and ended up sleeping with us again. They know what's going on but can't handle it, that make sense?
I would absolutely keep up their routines but like you're already doing fit in lots and lots of cuddles and time with mummy. If sleeping with them helps then so be it so pick your battles so to speak.
Trust yourself hun you know your little girls better than anyone. Totally confused you???