Can IUD cause terrible PMT or am I just depressed?

[Hotpants]

I have had an IUD fitted (copper Nova T380 so no hormones, just copper) and as well as the heavy periods I have been really really down, feelings of just can't cope any more etc. The thing is it is coinciding with other things happening at the same time, so it is hard to say what is causing what. I know the copper IUD causes heavier periods, but if it is a non-hormonal one, can it also cause big mood swings, ie, feelings of alternate rage and hopelessness? Has anyone else had this happen to them with just a copper IUD?