Negative pregnancy test. Cramps no period.

I should have gotten my period today but it really doesn't fell like I have a period coming on. About a week ago I had some cramps and I just thought it was pre period cramps and thought I was probably going to get my period early. But still not period and no more cramping. I have a huge appetite which is not that common for me. But I've been more active lately too so that could explain the appetite. But my pregnancy test is still negative. Is there any hope I may be pregnant this time around? How many women don't get a positive test until after a few day late on thermos period?