I got mirena (levonorgestrel) put in 4 months ago and since then have gained 20 pounds. I eat healthy and work out yet still continue to gain weight. Whats wrong with me?

Could be Mirena (levonorgestrel) As unlikely as it seems, the hormone in Mirena (levonorgestrel) can occasionally cause weight gain. If nothing else is different ; you continue to exercise and eat sensibly, i'd recommend you talk to your doc ; consider an alternative birth control. Have it removed if this describes your situation and use condoms or consider the paragard iud (non-hormonal copper based iud). Good luck.