Hello, Anon. Thank you for posting.
If you had your period after taking emergency contraception (and have not had sex since) this would indicate you are not pregnant. Even so, you might still have irregularity with the next period. This is a fairly common side effect of emergency contraception, for some women. If you are still concerned about pregnancy, taking a pregnancy test will ease your mind. We can't predict when your period will sort itself out. Each woman is different. Periods should get back to normal by the second cycle after.