So my bf & I had sex on Tuesday the 23rd, it was "unprotected" (we used pull out method) we did 3 rounds, he pulled out every time but then he went back in after about 30-40 minutes every time. I was supposed to get my period on the 26th and it's now 3 days later and still haven't gotten it. I'm usually never regular, For the most part I'm always late by a few days, I've never been regular. I've been having pretty strong cramps all day today which started light yesterday but got stronger today ... I always get cramps a few day(s) before I get my period but I've also heard that implantation cramps are similar to period cramps. Should I be worried??