missed period on IUD??

hey ladies just wondering if anyone has had this sort of issue with the IUD?? i currently have paraguard (the copper/non hormonal IUD) and have been having some complications. i got the copper IUD over a year ago and have had a pretty regular heavy period with some cramping every month. this month however i had very light spotting and no period. ive been spotting since december 11th and it is now the 24th. some other symptoms ive been having are head aches, heartburn which i have never experienced until recently, nausea, bloating, and fatigue. i also have a uti so burning while urinating and frequent urination as well. i took 2 pregnancy tests and both came out negative. what could this possibly be? can anyone relate??