2 year old head falling to side, cannot stand or sit now. symptoms started yesterday she just moved to california, 2 weeks ago. very vibrent and talking two year old, she is my grand niece

Anytime : Anytime a child who can sit, stand, walk and talk stops being able to do these things, they need to be seen emergently. These could be signs of a serious problem with the brain such as bleeding, infection, stroke or tumor. You should call your child's doctor if she has one yet in california. If she does not, then she need to go to the emergency department. Legal disclaimer: I am providing this general and basic information as a public service and my response to this question does not constitute a doctor-patient relationship. For any additional information, advice, or specific concerns, please speak with your own physician. The information provided is current as of the date of the answer entry.

Go to ER now: As stated by another, this could be life threatening, and the earlier she is examined, the better.