You can get this from GUM, CASH clinics and from some pharmacies.
You should also go to a clinic to get checked out for any potential infections.
This form of emergency contraception consists of a pill containing a special dose of the hormone progestogen. The emergency contraceptive pill can be used up to 72 hours (three days) after sex.
The emergency contraceptive pill should be taken as soon as possible after having unprotected sex, and no later than 72 hours after.
Whatever the reason you had unprotected sex the result is the same.
You need a quick check up to see if you caught something and to find out if those sperm found an egg.
Guys will need to get theirselves checked out too - although they might not be pregnant they might have picked up something nasty.
It happens.
Rather than pretend it didn't happen you need to get things sorted straight away.
You only need to look at how many STIs there are to realise you are better safe than sorry.