Had sex a month ago no condom but he pulled out and had my period a few days later now a month later i'm four days late no symptoms ...pregnant?

Withdrawal: This method has a high failure rate. You may get home pregnancy test.

Take a test: Alot of reasons for late periods besides pregnancy. If negative test them not pregnant and if still period seek out a doctor. You can ovulate anytime and become pregnant but norm is 14 days prior to your menses. I hope this helps.

Unlikely: There is a fair amount of variability http://www.nerdpocalypse.net/female.html cannot say in your particular case, but generally,