Hi,
I have the Paraguard IUD so it is completely different from what you have however, what struck me as unusual is your symptoms. I got my IUD November 2006 ever since then every month around the time of menstration, for about a week, I have these terrible pains on my left side. They are so bad sometimes I have to just sit. I usually take tylenol and they go away. I just have no idea what they are; they are NOT period cramps. The pain feels like its under my left rib or a little lower and deep inside. Also, I too, spot several days before my period and sometimes days after. My periods went from 3-5 days to 10. I don't care for it. However I do not like hormone endused birth control so I choose this. it is working obviously but with some weird side effects. I have had 4 ultrasounds by my OB because they can't explain the pain either and they are stumped. Everything appears normal in the ultrasounds. So for now I will wait, hoping that nothing is going wrong.