I hope this situation has already been taken care of in the emergency room, but for anyone reading rather than sitting in the ER, please don't!
Chances are very good that during insertion bacteria were introduced or you are having an allergic reaction to the mirena. Either case is a medical emergency, particularly the combination of swelling of the urethra shut, flu like symptoms (systemic illness) and massive vaginal swelling.
Again, I hope this has already been addressed successfully.