Hi all!

So here's my situation, I'm usually pretty regular on my periods, between 28-29 days. Back in December I started on the 11th, January on the 12th, and by surprise, February on the 6th, almost a full week early. I calculated my period from that date, and should have started between the 4th and the 5th of this month, but I have yet to see any blood! My boyfriend and I were intimate on Feb 7th, Feb 14th, Feb 17th, Feb 19th, and March 1st (all no condom, he pulled out several minutes before). I've been having cramping all week as if I'm going to start my period, but I've taken 4 pregnancy test (Two First Response Digital, one Clear Blue digital, and one First Response pink line) all of them have been negative. I don't have any "real" pregnancy symptoms, but my cervix seems to be pretty high up there, to the point where I can't reach it. I'm wondering if starting my period early last month could have something to do with it, but I'm not sure. Any suggestions? Thanks :)