I took norethisterone to delay my period for 4 days, I only started taking the norethisterone a day before my period was due and I didn t take it correctly some days took one or two tabs, but it still worked, no period came. Had unprotected sex with my partner and when I got home from my trip 2 days later my period started, now i have a niggling feeling on my lower right side almost like my implantation cramps that I had with my first child. Is this even possible whilst on a period? I had unprotected sex before I started the norethisterone and took a pregnancy test before it that said negative