Really heartbroken and confused.

So I’m not exactly trying for a baby, but I’m definitely not using protection/any kind of birth control. I have NOT gotten my period all month and today is the 30th, which makes it the second to last day of this month and I’ve gotten absolutely nothing. No period. No cramping. Nothing. But yesterday I took a pregnancy test and it was negative. This morning at 7:30am I took another pregnancy test and that one is also negative.. I just don’t understand why it’s not positive😞 I’m not too stressed out, I’m not losing too much weight. I’m perfectly healthy. I just don’t get it..😞