Bleeding for a month - how long does it take for the copper IUD to settle?

I got my copper IUD in early December last year, as I didn't want to use hormonal contraceptive. The first couple of months were painful and I experienced heavy bleeding, but that subsided and seemed fine for a while, but the past two months have brought me bleeding at random times, and for the past 3 weeks I've had a constant, albeit quite light, flow of blood. It's so annoying, and ruined some of my clothes!

The main question I want to ask is - is this normal for the copper IUD, and is it likely to subside soon? I'd have thought that after 9 months it'd be back to normal cycle, which is naturally pretty regular and manageable.