Delayed periods (late by 2 weeks) I do?

I am a married woman. My periods were due on 26th April but haven't got it so far, its late by 14 days (today is the 15th day). I took a home pregnancy test (hcg test) just four days after my missed periods (i.e, on 29th) but it came out negative. I got a little tensed after a few more days and went to see a Gynecologist at a nearby hospital on 5th of this month. She insisted to wait for 5 more days and take the test again on the fifth day. As told on the fifth day, I took the test today and it came out negative.. My period cycle is usually normal 30-33 days , I can remember only one occasion when it was delayed by 9 days which happened almost around an year ago but it has never been this late. I am a little worried, can you please suggest me what should I do?