advice!

So I've had the mirena in for 2 years now, and I haven't had a period for a year nearly. I usually get cramps every now and then but nothing too bad. But today I've been in pain and getting quite bad cramps, and noticed some bleeding. I've also felt sick and queezy all day. Anyone else had such a gap between periods with the mirena? I'm worried something might be wrong and it isn't a period.