I've been having similar things happen to me during this last year, and I have an IUD. I missed a few periods and my breasts swelled ridicoulsy. But I wasn't pregnant, thank goodness. I have enough kids. Anyway, just take a test and find out, there's no harm in being safe. There's always a possibilty that missing one pill can result in a pregnacy, I got pregnant with my daughter 8 weeks after I had my son, because I missed ONE pill. It can happen.