You should see your health care provider, just to be safe. It could be hormonal (ovarian cysts maybe?), the IUD could have moved...it could be a few things, your health care provider cna do an exam and tests if needed.
Just in case anyone is curious- I went to the dr today and after doing a lot of tests- pregnancy, std, and using a vaginal and regular ultrasound- they found a lot of fluid on my right side and sent me to the ER. There I got a ct scan and they told me it was a ruptured ovarian cyst. Sent me home with pain meds. Luckily these things started working cause I had been in so much pain for almost 20 hours!
Very glad for the update :) I am glad the doctors figured out what was wrong!