Period or pregnant? 15 and confused.

me and my boyfriend had unprotected sex about 3 weeks ago and it was my first time. he didn't ejaculate inside me, but it was close.
i bled a bit and had some spotting for about 2 days, which i've heard is normal.
i think my period came a week earlier than it should have (if it was my period), is it normal for loosing your virginity to make your period early? it wasn't exactly blood, well it didn't look like it, it was brown not red and lasted 5 days.