Aching pains.. symptoms of plan B pill?

My last period ended on the 6th and I had to use the plan B pill on the 12th because our condom broke, and it is now the 18th. This morning I woke up with upper abdominal pain and as the day has gone by the pain has progressed to my lower and upper abdominal as well as to the right side of the middle of my back. It is just really soar, feeling like its brused but its not. Is this one of the symptoms to taking plan B or should I be worried? Thanks.