Frustrated!!

I started BC for the first time ever on the first day of my period Feb 20th. I didnt even last 2 weeks on it as I stopped the BC the 2nd friday of the pack. I was regular before I started the BC. I wasn't consistent with it as I was taking it at different times and was taking it late. I had unprotected sex day after the last pill. Had breakthrough bleeding with lots of EWCM, 4 days after the last pill (March 7th) BTB lasted 5 days. I had unprotected sex on the 9th , 10th , 11th & 14th. Since then, I havent bled at all. I was expecting to get my period on the 17th if my cycle was regulated. I have had crampings since my expected period date, but pregnancy test says negative. I'm frustrated and annoyed. The BC paper said this.