Negative pregnancy test but still no period??

Two weeks ago I had sex, he pulled out but I was not on my fertile days, and supposedly a week or so later after sex I was supposed to get my period. But I missed it... being 6 days late and two weeks after having sex, I took a pregnancy test which came out negative and I still have not gotten my period.

I am concerned because in February I had taken a Plan B to not get pregnant obviously and this time I didn’t want to take it because I felt like it would alter my system all too much... I know the day after pill causes your period to be irregular for a while but I just don’t know! Can anyone hell me? I’m 17 and I am under a lot of stress because of this