Hi R. -- I love your name! It looks like you had the Mirena inserted right after you had your son -- is it possible that some of this is a reaction to childbirth and new motherhood and not to the Mirena? I ask because after I had my daughter (much, much later in life than you) I had post-partum depression and I held on to the pregnancy weight for nearly two years, even though my weight had been very stable and normal prior to childbirth and I threw everything I had to get it off. I only ask because childbirth DID give me all the issues you mention except for hair loss, and the Mirena gave me none of them, so my tendency is to wonder if the thing that has caused what sounds like a state of hormonal uproar in your body would more likely be the thing that causes major hormone shifts and surges rather than the thing that just affects hormonal levels right in the uterus and that is designed not to affect hormone levels throughout the body.
Just a possibility I thought I'd raise. I have heard of Mirenas causing problems, although not of this sort. I am very fond of mine, particularly of its effectiveness and the "sex any time with no prep" aspect, and, for me, I find it MUCH less troublesome than any birth control pill as regards weight gain and emotional stuff, so especially as young as you are, I kind of hate to see you give up the Mirena wiith its high reliability and easiness IF it isn't what is causing your symptoms.
Best of luck -- depression and insomnia are miserable!!!
M.