well you did have unprotected sex which leads to pregnancy, so you obviously have a high chance of being pregnant and i'm sure you knew that when you were having unprotected sex anyway.
anyway, not trying to be rude, but this is a forum where teens want to keep their babies, if you're considering abortion you might want to also post this in the abortion forum as you might get more positive feedback than you would here because nobody here is going to tell you to abort your baby.
you could probably take a test right now, but im not sure if it'd come out accurate or not. take one now, with your first morning urine if you feel like you really think you're pregnant, and if it comes out negative and you still haven't gotten your period in a few weeks than take another.
please keep us updated, and good luck.