Help!?

I started Metformin mid April for high insulin just found out I have pcos. But before I started metformin my periods were relatively regular 21-25 days 3-4 days long. And today my period was due an I still haven't gotten it. I'm having pretty bad cramps But o figured it's bc my pcos but I never had them before. And I've had them for about 3 days. I have never been late on my period always early. what's going on? Don't wanna assume I'm pregnant an get my hopes up. As I had a mc at 22 weeks in November 2015.