Plan b and birth control

I currently take birth control but I forgot to take one pill and I took another later than I was supposed too. My SO and I had sex and the condom slipped off, but the ring was outside of me. So being that I was nervous I went and took plan b. This was all the 3 weeks before my next period. I finally got my period on the expected day and it was super heavy with horrible cramps but only lasted 1 day? Could this have been because of the mix of all the hormones??