Period Stressin'

So on Saturday (the 25th) I'm getting married. I was supposed to start my period on Wednesday or Thursday of this week (so the 15th or 16th) and I haven't yet. My periods are five days long which means I NEED to start no later than Monday. I'm so stressed about it I want to puke. I don't want my period to ruin my wedding day or night. And I know they say stress can delay it but I can't calm down I mean I'm getting married on Saturday! And I haven't started my period! SOS!!