Negative pregnancy test cycle day 50

Here it goes. Has anyone ever been pregnant and then had your pregnancy test not show positive until a few weeks after your missed period? My cycles are usually 33-36 days. I have never been this late before ever! I've taken a few pregnancy tests which were negative. Should I give it a few more weeks before calling my doctor? I get everyone is different but how long does one go with a missed period before calling the dr for an appointment?