Hi, I just turned 17 about a week ago and im dating my first boyfriend. We just had sex and it was both of our first times, it was just once! he used a condom. Its been two days and i took my tampon out today and along with blood, there was dark yellow mucusy stuff on it. i was supposed to get my period the day after we had sex. do i have blood because i had sex or because i got my period? ive never had this yellow stuff before and it is scary. i dance ballet very seriously so maybe it was because i got sweaty at ballet with a tampon in? or should i be worried about infection or sexually transmitted disease?? it doesnt hurt to urinate. is this normal??