Missed period

TH
I have missed a period for the first time ever.  I have tested 4 times with different types of tests over 2 weeks, and I'm not pregnant...
I have a ob/gyn appointment April 3, but my husband and I feel so anxious... 
After trying for 10 months, we thought this was it.... 
Can anyone relate?  What is wrong with me ?  Why a skipped period now?
Thank you