Can you get pregnant when you have an IUD?

I have had this IUD for a little over a year now. But the past few weeks or so I have been feeling funny. I haven't gotten a period and I have had funny cramps, I am all of a sudden so tired that I am having to force myself to stay awake even though I am getting lots of sleep at night. I don't have morning sickness or anything like that, I just feel different. I know that with an IUD I might not have a period all the time. But I was just wondering if someone can get pregnant while having the IUD?