Menstruation/birth control issue?

A little TMI for some people, possibly, but I’ve been getting my period twice a month, off and on, for a little while now. It’s starting to drive me crazy because after I have my period the first time, I’m obviously not prepared at all for it to happen again in the same month. This time in particular, it was only about ten days between cycles.

So my question is… What the heck is going on? I’m on birth control pills that contain no sugar pills (because I have the kind of migraines that make the “normal” BC particularly unsafe for me) called Lyza (norethindrone), and I’m wondering if that might be why?

I’ve had a very light and short (3 days tops) cycle my entire life, so this baffles me. This has never happened to me before and it definitely only started happening after I started these pills, so I tried to look up side effects for what I’m taking, but I didn’t see anything about having two periods in one month.

Have any of you experienced something similar? On or off birth control?