My daughter's father has full custody of our daughter. I get visitation every other weekend. He dropped her off to me 10/28/2011 and as of today 11/17/2011 I still have her. He has not called nor will he return my phone calls. At what point does this become child abandonment, or do I legally have custody of her?

Depending on where you live (ANY question on law needs to include your general locale as laws vary by area.) its not abandonment at all. Please see this sticky post: https://www.askmehelpdesk.com/family-law/child-abandonment-read-first-364259.html

And no you don't legally have primary custody. As long as the court order stands the custody arrangement remains the same.

I would wait until after Thanksgiving, and if he still hasn't responded to you, I would file a petition in court to have the custody order modified.