Perhaps you're getting an early period. Or you've got flu or some other abdominal pain.
Unfortunately, the more stressed you are, the more likely your period will be delayed.
So, here's what to do.
Hang in there, at least for a couple of weeks, and try to remain calm, but also purchase an over the counter pregnancy test. Follow the directions on the box and do not take the test any earlier than the directions say to.
If you get your period, then of course don't bother with the test and squirrel it away. And head to your doctor or Planned Parenthood and get a second form of birth control in addition to