I have had a para-guard IUD for 8 years. I have had irregular periods for the whole time.?

October 2010 was the last period I had. Every month I have my regular PMS, cramps etc. Every so often it is followed by very light spotting. I have missed a month here and there but not this many. I am not pregnant and have not had the money to go to my gyno. I have an appointment for next month but for now I was wondering if anyone else has had anything like this happen with a non hormonal IUD?