Does IUD Cause Irregular Menstruation?

Hi, i'm 26, i have an iud fitted, it's a non hormonal copper t. I had i fitted 6 months after giving birth and had a slight infection after 4 months which was cleared by antibiotics, my period were regular, approx every 32 days. at the beginning of this year i missed 2 periods and then had two periods and have now had no periods for 3 months! I also feel quite low in mood most of the time and have mood swings regulary, i sometimes feel like i am about to have a period but then syptoms go again. I have done a pregnancy test recently and it was negative. i have one sexual partner.