2 months late.

I have had a regular period like clock work for the past 15 years and have been tracking every period for the last 3 years. I have missed august and septembers period. I have taken 2 home pregnancy tests in august which were negative. Still no period when september came around so i took a blood and a urin test at the doc was negative its been a week. Has anyone had this happen and still be prego??