AF was due feb 27th... No period yet!

Roland
My name is Kelly, I was supposed to get AF yesterday, bought a pregnancy test and got a bfn yesterday morning!! :( feeling some cramps, and a little nausea. Could it be that I'm pregnant, or is it all in my head? I haven't had any spotting only cramps. This is our second ttc, really wanting to have a baby soon. :)