What Causes Prolonged Periods And Mood Swings While On Mirena Coil?

I have had Marina Coil for 2 years but have been bleeding for weeks at a time and has never truly settled down..I go from having a full period to wiping myself and there will be blood or brownish colour and this can last up to 3 weeks at a time. My mood is also terrible I feel really uptight all of the time. I had this coil before I had my first child and it was great I never had a period. But since the birth of my second it s been hell. I get smear test every year as I had abnormal cells removed a few years back and my yearly coil checks have been fine. What is wrong with me? I m thinking of going to my Family Planning on Monday to get it removed? Do you think this is best option?