Missed Period, IUD in for 9 Months, Weird Things Happening...?

I have had a Paraguard IUD in for 9 months with out a hitch, I have never skipped a period and have been on time each month. It has been anywhere from a week and a half to two weeks since I should have gotten my period. I have been spotting brown discharge for the last two days. Four days ago I had pain on my left side all day, the kind that makes you want to lay around in your pj's all day. Ever since then I feel bloated, emotional and have been having gas like pains in my legs and upper back, towards my left shoulder blade. What could be happening? I have no insurance and am waiting to see if anything develps. Oh and I did take a pregnancy test and it came out negative. Thank you all!