Late Period & Negative Pregnancy Test: Possible Pregnancy?

Question
Hello,

My menstrual cycle is usually about 30-32 days. My last period was on April 18. I took a pregnancy test on May 21 and it came out negative. I've been a bit sick on and off - a cough that won't go away for the past month. I've been sick before but never has it affected my menstrual cycle to the point that I would be late. But, I do hear that it is possible.

Anyway, my questions are: is it possible that I could still be pregnant? I haven't tested again. When would be a good time to test again if I don't get my period? A co-worker of mine had told me that she was pregnant despite a negative pregnancy test for two consecutive months before confirming it with her ob-gyn. She now has a healthy baby boy.

My husband and I are hoping to be pregnant as this would be our first child.

Thank you in advance.  

Answer
If you have a 30-32 day cycle, ovulation occurs on cycle day #16-18. If your last period started on April 18, you would have ovulated on May 3 or 5.  Therefore, you could have conceived if you had sex between May 2-7. A pregnancy test would not show a positive result until 14-21 days later. The best time to take a pregnancy test is seven days after missing your next period. You were due for your period on May 17-19. Therefore, if  you do not get your period by May 24-26, take another pregnancy test.