Cramps

Anyone else notice that you're totally fine until you realize you're on your period and then the cramps just hit you superhard like Ha! We're here! Sometimes I'm crampy when my periods coming, but it seems like they don't really hit me until I confirm I started my period. That just happened to me today. I was fine all day until I went to the bathroom and surprise! Two days early, and now my cramps are practically crushing me. I am super miserable and in lots of pain. What IS that?!