Females normally cycle every 6 - 8 months, these false pregnancies can occur about 6 - 12 weeks after a cycle. It's pretty crazy because they can even show signs of what appears to be a normal pregnancy! Some dogs may display these signs while others may not; nesting, mothering inanimate objects like soft toys, lactating and even appear to be in labor. Usually, they resolve in about 3 weeks but, it may take some females longer so its important to keep note on a piece of paper each step in the process. What you'll likely want to do is have your little girl spayed but that can't be done safely until the false pregnancy is over.