Also, I lost weight on Mirena

I LOST weight on Mirena. I am 5'9" normally 135lbs and a fitness trainer. I was down to 126lbs. Thats a lot of weight to loose when you are eating 10xs more Sugar and junk food from all the cravings I had.
I know most women would hate me for complaining, but being that skinney, looked and felt unhealthy. I'm up to 130 now.
Muscle weighs more than fat, and I think that on Mirena, I was loosing the ability to gain muscle. So with my muscle loss, my weight dropped. I train to gain muscle, and no matter what I did I couldnt when I was on Mirena. The last 3 weeks I have have worked out the same and easily started gaining more toned, muscular arms like I am used to.