I Had Sex On The 24th Of December It Was

I had sex on the 24th of December it was my first time. It was 4 days after my period it would have been 8 days but my period lasted longer than usual. I saw my period on January the 5th it ended but now a week and a half later I feel dizzy and nausea. I can't buy a pregnancy test or go to the doctor without a parent please help me