Go see your doctor for a blood test.
I was supposed to get my period on April 12, and I took several pregnancy tests...including one on April 17, which all came out negative. I was super hungry and tired though, so my husband convinced me to take another one on April 19 that came out positive!
Maybe try waiting another 2 or 3 days and then take another test? There can be a little variation by a few days as to when it shows up on a test, I think. I've been reading that a lot of women won't get a positive until 2 weeks after missing their period. Good luck! My thoughts and best wishes are with you!
Can you go get a blood test done? That will comfirm for sure better than pregnancy tests. Inform your family Dr.