How long ago did you have sex? Was it protected? You said you're sort of trying so I'm guessing a no, did he cum inside? So many different factors to determine that. Best suggestion from me is to let time play out for a few days, maybe a week at most depending when your period is suppose to come, and if that doesn't work, go see your Doctor. You could also google those symptoms too, that usually helps me when I have a problem or when my girlfriend is experiencing odd things about her that worry her.