"ladies, let me tell you this pill works! 
my boyfriend and i had the condom fail right during the middle of my cycle. i went to the pharmacy about 9 hours later and bought some. right after i took it i felt fatigued the whole first day. i did experience some other side effects as well seeing as i have never been on any hormonal contraceptive. i had cramps for the full two weeks until i got my period as well as breast tenderness. 
the week after i took the pill i felt nauseous, had sore breasts, sore back, cramps, and headaches. i thought i was pregnant and got really stressed out. 
i got my period right on time though despite my stress. my best advice is to just relax and wait it out. easier said than done i know!"