My girlfriend and I had protected sex a few weeks back. We've had sex before but this time was different. Being the paranoid freak that i am i asked her to take Plan B for the first time for some extra protection. A few days later she had some bleeding similar to a period. i told her that it was a side effect of the Plan B. fast foward a few weeks. My girlfriend should be having her period sometime this week, but instead has some spotting and nausea. could this be a lighter period caused by the Plan B or should we be worried?