You seem to be having the symptoms of menometrorrhagia. Various factors causing it are endometriosis, ectopic pregnancy, hormone imbalance
,endometrial hyperplasia, polyps, use of IUD’s and depo shots, sexually transmitted diseases, PCOS and benign and malignant pathologies of the uterus. What you are having is metrorrhagia due to mirena
I would advise an gynecologist’s evaluation and an ultrasound uterus to ruled out the above possibilities.