Help please ! I felt like I was about to get my period, with the cramps and things . And on that…

Help please !

I felt like I was about to get my period, with the cramps and things . And on that very day me and my boyfriend had sex (20th of this month) I read that it's unlikely to get pregnant before you get your period anyway ever since then I haven't gotten my period it's been over a week now I'm getting kinda worried . I read online that sex maybe can delay a period ? If not should I take a pregnancy test after 2 weeks ? If I haven't gotten my period .