have you been/do you track your periods? do you know when your last period was? You can get pregnant anytime you have unprotected sex its all a matter of risking that chance And it actually hppening to you. Test closer to your next expected period.
A line is a line if youre getting a positive on the test within that 5 minute window or so and it is not an evaporation line than your are more than likely pregnant. If to yourself you dont believe it yet, wait a few days and test again.
You period isnt "scheduled" to come the same day everrry month every time. Wait and within this week if you still have yet to get it then test. Stress can most definetly throw off or delete your period.