Why Are My Menses Abnormal With Spotting And Brown Blood Post IUD?

hi my name is kllkle and my question is i had an iud put in jan 2008 and i have bleed really heavy and had my periods for about 3 weeks at a time all a sudden this period aint the same its just spotting and not a normal colour to me its a brown colour and i only spotted for about 4 days and only filled id say 1 and a half pantie liners plus my mood has changed im more moodyer is this something i should be worryed about please help me find my answer thank you very much