What Causes Stomach Bloating And Breast Soreness Inspite Of Using Plan B?

Hi,I had unprotected sex on Jan 1st with my boyfriend. My last period was Dec 20th in a 25 day cycle (so it is possible that I was ovulating when we had sex). I took a "Take Action" pill (generic Plan B from Walgreens) in under 24 hours. I've been feeling bloated and my breasts are sore. My period is due on Jan 13th. Is it likely that I'm pregnant?