It is unlikely but there is always a chance of pregnancy when having unprotected sex. I wouldn't worry too much and just wait and see if your cycle comes on time.
Good luck!
Hey there,
Its highly unlikely that any sperm swam into you from the outside, as sperm cannot live outside the body for long. You should be more concerned about pre-ejaculate (precum) which has a more likely chance of getting you pregnant. The pullout method is about 86% effective when done correctly.