Getting an IUD placed is on up there with most unpleasant experiences of my life. At least it was quick, the doctor who did it was clearly very practiced, and I'd had a valium and some pretty strong ibuprofen beforehand, so that helped, but my god was it awful! I'm just really glad I got my uterus removed so I never have to get another IUD. It's a special kind of pain, having stuff shoved through your cervix, that's for sure.
I'm sorry you had to go through it, hopefully you can take some time to recover and won't have to do it again for several years!