So my period starts on the 18th every month except this month it says it was suppose to on the 19th, and I still haven't started and it's the 21st. I'm having ALL of the period symptoms I usually have, like bad period cramps, gas, direeah, sore boobs, and bloating also bad headache. I hit that it didn't start on Friday and now it says I'm suppose to on Tuesday, Any ideas?