Did you guys use any form of contraception? If you did, there's small chance you could br pregnant, and that chance grows if you did not use any. Any time you have sex you run the risk of pregnancy. Even if he does not ejaculate inside of you, there could be sperm in the pre ejaculate fluid that he may or may not notice coming out.
Your period could be different from a number of things, one of which is pregnancy so I wouldn't panic quite yet. What you should do is take a home pregnancy test when it says you can (around two weeks after the last time you had sex) and it'll give you a more accurate picture if you're pregnant or not.
NOTICE: The information provided on this site is not a substitute for professional medical advice,
diagnosis, or treatment. Never delay or disregard seeking professional medical advice from your
physician or other qualified health provider because of something you have read on Wellsphere.
If you have a medical emergency, call your doctor or 911 immediately.