What Causes Heavy Periods With Cramps While On Levlen ED?

I'm on levlen ED, and have taken about 35 days worth of active pills so far (skipped first sugar pills) but for the last week I've had spotting that has become increasingly heavier. I've decided to begin the sugar pills as of 2 days ago, and I now have an extremely heavy period, and extremely painful cramps. (I've had one child, and these cramps are almost as bad as my first hour of contractions when I had my child.) I'm not sexually active, so there's no chance that I'm pregnant again. Would it be recommended to try a different brand of the pill?