I am 6 days late for my period I have been feeling VERY tired and have has mild menstrual cramps for the past 10 days. I took a HPT today and it came back negative. But I 'did the deed' unprotected only 6 days before my period.

My period is never this late and I don't know when I ovulate. Is it possible to ovulate 6 days before your period is due? Is it too early to test as if I were I would only be 10 days pregnant? If my period still doesn't come would taking a blood test on Wed (2 weeks after conception) be too early or should I wait longer to go to the doc's?? Thanks