Since it's been less than 72 hours since unprotected sex, the emergency contraceptive pill is still a reasonable option for you. It works best the sooner you take it, so taking it today rather than waiting gives you the best chance of preventing pregnancy.
Next Steps
You can get the pill over the counter at any pharmacy. It may make your next period come a few days early or late, and can cause some spotting or nausea. Please use condoms or another regular method for the rest of this cycle, since this pill doesn't protect you against sex later on.
Health Tips
If your period doesn't arrive within a week of when you expect it, take a home
pregnancy test and consult your gynaecologist.