I had sex with a condom on october 13th, and he also pulled out. i was expecting my period on the 20th, but came on 18th and lasted 3 days. pregnant?

Probably not - UPT?: You are probably (90%) not pregnant however the only certain way to know for sure (99-100%) is to check an over-the-counter urine pregnancy test (upt) as soon as possible. At your age fertility is maximal and you may have up to a 20-30% chance of pregnancy per cycle with unprotected vaginal intercourse. Condoms help but withdrawal does not - you still have a 10% chance of pregnancy. Folate (folic acid) 1-5 mg.