Are these signs of early pregnancy?

First day of my last period was 5th Nov 2010, I have a regular 27-28 day cycle, I calculated my ovulation dates to be around 15th-20th Nov, so me and my partner have tried everyday during this ovulation window. About 3 days ago I started feeling twinges in my lower right side abdomen, and period like cramps, which I had again this morning, followed by more twinges and feeling nauseous.. isn't this a bit too soon?? I'm not due to my period for another 2 weeks (ish)... could these be early signs of pregnancy??