IUD = heart palpitations?

Christina
I had my Mirena IUD placed about 5 weeks ago after 12 years on the pill. Ever since I have been having weird heart palpitations - like my heart is skipping a beat. It only happens sometimes (but does happen daily) and usually goes away after a few minutes. A little googling tells me this isn't uncommon. Has anyone else experienced this? Did it go away for you?
I'm kind of freaked out!