Well theres always a chance. But it's possible sex shortened your period. Sometimes it does that to me, or it will stop it for a day and then start again too. It s way too soon to take a test or anything. You will have to wait till the time of your next period to see if it comes.
Like the other girl said you have to wait to take a test and see but you might not have had a short period it could have been because you were a virgen he broke your hymen which can cause bleeding to!
Anytime you have sex it is possible to get pregnant. All you can do is wait another week and take a pregnancy test. Good luck.