If you've had unprotected sex in the last five days, you're still in time to use emergency contraception.
If you think you could be pregnant you should do a pregnancy test as soon as possible. You can buy a test to do yourself from the pharmacy or supermarket, or you can ask for a test at your general practice, any young people's service, a contraception or sexual health clinic, a pharmacy (there may be a charge), most NHS walk-in centres (England only) and GUM clinics.
You can do a pregnancy test from the first day of a missed period. Tests that are done earlier than this may not be accurate. If you don’t have regular periods, the earliest time to do a test is three weeks (21 days) from the last time that you had unprotected sex.