Worring about things doesn't change a thing. Take it one day at a time and do the testing like they said. The world is what it is so don't bother to worry. A lot of things can cause a missed period.
stay calm
bbq33
like heatherlynn said pregnancy isnt the only thing that affects your period
get a blood test done. there are other reasons that your period is late or not showing up. if the blood test comes out negative go to an ob/gyn for an exam to be sure there are no infections or anything.