Hair Loss?!?!??????

Erin
Should I be worried if my hair is thinner then normal? 
I've had the mirena IUD for about two months now and I've noticed my hair is a bit more thinner then it was before I got the mirena, there's no boldding but it's definitely not as thick as it normally is, 
is my hair going through its yearly circle or is it the mirena and if it is the IUD will it grow back and go back to normal?