Hey. You sound like a pretty smart girl, except for one thing! I would be a total hypocrite though for saying how dumb it is to not use a condom , because I just found out that i'm pregnant as a result of not using them

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My advice to you would be to stay clam, don't rush into telling your parents yet. Try and figure out your menstrual cycles. When was your last period? What day did you have sex on? Did he ejaculate inside of you? There are only about 5-7 days in a month that a woman is fertile. So, let's hope the day you had sex didn't fall on one of those days. In a normal menstrual cycle, a woman ovulates about 2 weeks after the first day of her last period. You're most fertile 2-3 days before ovulating, the day of ovulation, and about a day after. ( the egg only survives for about 24 hours).
It might help you to look at a calendar and count 2 weeks from the first day of your period, and then see if the day you had sex fell into that week. If it didn't, you can probably stop worrying. If it did, the only thing you can do is wait and see if you get your next period.
Good luck, i hope every thing works out for you.