Hi, My Name's Ashley, I Have A Problem, Im Not

Hi, my name's Ashley, I have a problem, im not sure what is wrong but I have a greenish thick like discharge and also have an iud, and I have one child I also have had the iud before I had my son, and had my period the whole 4yrs , now I have a new one and had it for 7mknths or longer, and had my period so very light now I missed one? And that discharge what could possibly be wrong?