False/Phantom Pregnancy

Question
What are the characteristics of false/phantom pregnancy?  Gracie Lou is a 1 1/2 year old toy poodle. She went out of heat approximately 3 weeks ago. Lately she has been acting strange. She seems to be nesting her small stuffed toy animals and if you get close to her when she is doing this, she growls.  She sleeps with us and lately likes to get between the blanket and comforter.  My husband tried to move her over in the middle of the night, she bit him and punctured his finger.  She had brought a tiny stuffed animal into bed and may have been trying to protect it. I don't understand this behavior. She is normally good natured. My co-worker suggested false pregnancy which I had never heard of. If this is the case how long will she exhibit this type of behavior and what can I expect? How can I help her?  I know she is not pregnant. We watch her very close and did not come in contact with another dog during heat.  Thank you very much, this site is very helpful to many people and pets!

Answer
You need to either get serious about learning about dogs, or get her spayed.  It is totally irresponsible to keep an intact female and not educate yourself.  And even more so to think about breeding.  It breaks my heart knowing so many dogs are slaughtered for lack of homes.  Then I see question after question from people failing to take the responsibility to either spay their pets or do the research necessary.