okay well i am 16 years old and i had my period last week on the 17 and it ended around the 23 or 24 i cant remember but even after my period is over i am having cramps and lower back pains and heartburn and my tummy hurts and i feel like im going to throw up sometimes. i have never had sex before but me and my boyfriend have had oral sex and i dont know what is going on :((( i saw that antibiotics canreally mess up your period and i took those for about three weeks at the end of may and beginning of june for a sinus infection and i also took antinflamatories for my knee so could these have messed up my period???? or i have been stressing over this all month so could this have made it weird to?? can someone help me??:((