Well first things first congrats on your baby girl.
As mentioned above, no doggie daycare will take her as she is too young and is not spayed yet. The youngest they will take is anywhere from 5-6 months and has to have a managers approval. (I work for one) Seeing that you work a lot of hours and that your little girl is still very young, you will probably need to look into hiring a private pet sitter to come in and check on her. The play pen idea is good, I just got mine in from ebay & I love it. We left Teddy and Lola alone today in their playpen for probably 3 hours tops and we came home to poop all over it along with their water bowl tipped over. It was a mess and if their poop isn't picked up from their pad fast enough they will eat it
I hope everything works out!