Abdominal Discomfort

I have had mirena since April 2008 and recently (2days ago) I had abdominal pain and I can no longer feel my string. The pain feels more like muscle pain, but I am confused. I don't understand how this pain comes from nowhere and it's not like cramps, its more muscle abdominal pain/discomfort and now I can no longer feel my strings, what could be wrong? What sort of pain would happen if it pertruded through my uterus? Whats wrong? I have a doctors appointment tomorrow, but I am stressing overly!!!!!