Как Plan B повлиял на месячные? Задержка, тесты отрицательные, что это? У кого так было?

How has plan B affected your period? I took a plan b on Sept 4th. I got some spotting/light bleeding on the 13th-15th. Is that considered my period? I’m 5 days late & negative pregnancy tests. I’m hoping it just pushed back my period a week late. I thought I started my period this morning but turned out to be just a dream.