Eptopic Pregnancy with IUD??

I have had my Mirena for about 3 years now. I have found the occasional cramping and spotting of darker brownish discharge to be normal and have has no scares as of yet. However, a few days ago the cramps started again except this time they are pretty intense. The cramps have lasted now 2 days and the spotting is currently more than it has been in the past and is very bright red. Could these be signs of a, rare anomaly on an IUD, eptopic pregancy or still within normal? Any thoughts? Thanks