Kyleena

I have the Kyleena IUD. I had it put in in April, bled for like a month straight and then things went back to normal aside from the occasional spotting. My periods were shorter for the most part and not as heavy as they were before. But now, 6 months later I had a really unusual period and once it ended I started having brownish small clots and things coming out. Today I had dark spotting and it’s more than usual. Does anyone know what this could be? Is it normal?