vw, that's normal with the Mirena. Everything I've read says that it'll settle down within a few months. I recommend (if you haven't already done this, which I'm sure you have) taking 4 ibuprofen (800 mg) every 4-6 hours and snuggling up with a heating pad.
I'm trying to convince myself that if I go get groceries right now, and then work out after groceries, I can take a nap as a reward. But I'd like to skip the hard part and go straight to the reward. Naaaaaaaaap....