You are dreaming about it because you think about it alot, probably before bed aswell. Unprotected sex is never safe even if the guy pulls out the precum contains sperm and can still get you pregnant, if you don't get your period you probably are but if you took a morning after pill you could have prevented this though they are not all that great for you, and I am aware you didn't know he came inside you at the time but i think you can take them within 72hrs of it happening, too late now anyway I wouldn't worry too much until you get a positive or negative confirmed test because there's nothing you can do about it until then, just see your doctor