Missed Period & Negative Pregnancy Test: What Could It Mean?

Question
My husband and I started trying to conceive when we went on vacation on May 1st. I believe (based on usual sensations in ovary area) that I was ovulating during the 2 days before we left to go away. From May 1-9 we had unprotected sex. My period was due on May 10th but its is now May 18th and I still haven't gotten it. I feel normal otherwise, other than bloating,some fatigue and mild, brief cramping. I have taken several home pregnancy tests and gotten only negative results so far.  Is it possible that I may be pregnant despite this?  I'm tempted to make an appointment with my doctor but not sure if it's too early. Any advice would be greatly appreciated.
Thanks!  

Answer
Hello Amanda.  Home Pregnacy test are very accurate, but they are not 100%.
Most of the time if you call your Dr. they will tell you to wait and see if you miss next month before you make an appt.
You should wait one week between test for best results.
If you are concerned you can make an appt. of course. They can do a blood test that is more accurate.
Good luck to you.