Copper IUD

I've had a copper IUD for 2 months now, and with my first period with it I noticed a lot of brown spotting for about 2 days before the initial fresh blood/actual period. After that period, I was intimate with my husband and wanting to finally go all the way without worrying about a pregnancy, I let him finish inside me several times. About a week later, I had a noticeable amount of spotting for about a week and was freaking out thinking it was implantation bleeding and that I was pregnant. He's in the army so he was only home for a weekend and I haven't seen him since then, but its a month later and I was having serious cramps yesterday and quite a lot of spotting so I figured my period was starting, but today I have almost none and no cramps! What is happening??? I just want my period to start so I can stop worrying. My period is already a week late, I just want some peace of mind.