Hello,
Amenorrhea during and after using Mirena IUD is a side effect of this contraceptive. According to an estimate nearly 23.9% women were having this side effect after using Mirena. But most of women have periods while on Mirena.
It is very difficult to precisely confirm a diagnosis without examination and investigations and the answer is based on the medical information provided. For exact diagnosis, you are requested to consult your doctor. I sincerely hope that helps. Take care and please do keep me posted on how you are doing.
It depends on how long you have had it. If you have only recently then you may well still get periods for a few months. Most women stop bleeding after 3 months some like me still are having periods 9 months later. It can take up to 12 months to not bleed and other women continue for years having a very slight bleed. Every woman is different and there is no set rule.
Generally speaking if it is not overly heavy or painful then it can be normal.
More information about your case would be a help to understand your problem.