frustrated !!!!!

Dezhane
So my period is 10 days late. I'm usually always on time or a day early. With a regular 29 day cycle. I am now on cycle day 39 :( but I am getting negative preg test. Could it be the test I am using? When should I go to the dr ? I didn't have this problem finding out I was pregnant with my first baby this is so frustrating! Help !