1 Neg hpt...no AF...what gives...grr?!?!?

My last period was from Nov 31st-Dec 4th and that was my November period. I still haven't had a period for Dec. I have all the symptoms and have for like 2 weeks now. I took a hpt test that was a few months old last Saturday and it was neg. Do you think I should retest or just wait for AF?