3 Missed periods on the trot but not pregnant

[bubblebath1]

Hey, I've got a Mirena coil which I've had for about 5 years so is due to come out, for all that time I've had periods (mostly normal, lightish) except that I've not had a period for the last three months - I'm due a smear test next week so will ask the nurse then but I'm definately not pregnant. I know that periods can completely stop with the Mirena, but after so long? Does that sound normal/ok?

Thanks x