You sound very much like me. I kept the IUD for 6-8 months (I don't remember, I have 2 kids :-). The cramps improved QUITE a bit, I didn't get lots of headaches and they went away soon, and the nausea improved would come and go. Mostly I got car sick. I didn't notice that go away. The blurred vision was weird because I thought the IUD may be to blame, and it got better right away after removal for about a week, then returned, and now is mostly but not quite gone (3 months after removal). I hope yours goes away!
I know it can affect you for 1-6 months after removal, and it's still affecting me. I got 2 periods and they were 2 days long instead of 4. So still not out of my system.
Good luck!
headache blurred vision lower abdomen cramps better with time wrong decision vision loss crap iud blurred vision cramps nausea headaches good luck periods