Mirena weight gain!!!

Felicity • 21- UNB- studying to be a dietitian-hypothyroidism
So I had gained about 40lbs before I got the IUD in, the. Once I got it in I gained another 30lbs and I just can't get rid of it.... I've had my IUD in for over a year now& my doctor says I'd be the first case for him, but my IUD is causing this (I also have a hypo active thyroid, I take medication for it) so I'm getting the IUD removed. Really hoping this is the source of the problem as I LOVE my IUD way easier then taking pills or having the patch! Anyways... Anyone else have or had this problem? Would love some stories! Or advice!