Pregnant?

Hey guys!!! I wanted to see if anyone had an experience like mine. 
I'm 7 days late, and on a new pack of my bc. I've taken three tests in the past week and all have said negative. I feel like I'm going to start my period? Super cranky, crampy. But still nothin!!! 
Is it too early to tell? Can you skip a month and not be pregnant? Help me out please :))))