Horrible cramping after sex with Mirena IUD

Hi there.. I have had my Mirena IUD for almost 2 years, and haven't had any problems with it. Last night after having sex, I was doubled over in pain, almost felt like labor pains. Today the pain isn't as bad, but it is still there. Last night I went and checked for the string, and at first i couldn't feel it. I waited a few minutes and tried again, and did feel it. It felt shorter than normal. Is it possible that during sex the IUD was pushed up inside of me?

Thanks!