I had unprotected sex and my boyfriend thinks he came in me but i took the plan b and now my nipples are sore and my pee smells what can it be?

When was last period: Determining pregnancy depends on when was the first day of your last menstrual period, timing of sex (how many days after first day of period), and whether protection was used. Without a condom and spermicide, pregnancy is always possible. If your period is late, take a home pregnancy test. If you have not had your period yet, you will need to wait until it's due to find out. Good luck!