I assume you were using a condom? If not, you might wish to read Ready or Not? –The Readiness Checklist and Safe, Sound & Sexy – A Safer Sex How-To.
If you did not use contraception, it is now too late for emergency contraception (the morning after pill). On top of that you both now need STI and STD scans.
Pregnancy tests sould be taken 14 days after unprotected intercourse or the 1st day of a missed period. A negative test should be reconfirmed by a second test 7 days later. You should date these tests from the last time tht you had intercourse as conception may have occurred at any of the 3 occasions.
We can't solve problems by using the same kind of thinking we used when we created them.
- Albert Einstein