This definitely isnt normal. Mirena normally caused decreased bleeding after few months of use.Eventually there will be amenorrhea
. The first thing to do is to have an examination,to make sure that the Mirena is in the correct place. Next get an ultrasound
to check for associated caused like adenomyosis
,fibroids etc. Also get your thyroid
tested. Loosing hair so drastically isnt related to this.You should be tested for other causes with regard to that.