Period Heavier after Year On Mirena?

Had Mirena inserted 6 weeks after having my first and only child 2 years ago. Soon after insertion my periods started to decrease in amount and time. For the first year i was only spotting or very light period so in my mind im like "yay! pretty soon im not going to have my period anymore" every girls dream right? Well this past year ive slowly been having heavier and heavier periods. Like normal ones before i got pregnant, im actually using tampons again...ugh....i haven't been to the dr and right now i really cant afford to go for something like this so im asking if anyone has had this happen with mirena. Ive already viewed their site and all it says is that if your period get heavier to see your health care provider but thats it, no explanation as to why this would happen. Need your advice or experiences. Thank you in advance.