IUD Weight Gain

Has anyone gained a considerable amount of weight while having the IUD? In the past year I have seriously gained about 20+ lbs and I had the IUD inserted in January 2015. Nothing about my eating habits have changed. Yet I seem to be getting bigger and bigger. I read that 5% of women using the Mirena gain weight; however, weight gain with other BC is attributed to estrogen which the Mirena has none. Maybe I'm just going crazy but has anyone else experienced this? And if so if you got the Mirena removed did you start losing weight?