Anyone ever had the feeling like you've done a ab workout, but you haven't and been late with a bfn. I'm just concerned because one, even with the Gardisil shot, I had a case of the cancer virus HPV and undergone a procedure and two I have endometriosis in my family. I have never been diagnosed with it, but was wondering anyone's take on this matter. If my period does not come by Monday I'm going to give my doctor a call.