Mirena Users I could really use your advice

I had the Mirena iud put in about a week ago and I'm still spotting, when I bend or sit a certain way I can feel pressure in my uterus, it doesn't hurt or anything, it's just a slight pressure, and my sex drive has decreased. I chose to get the Mirena because I have bad periods and am allergic to the hormone in the pill. Is this normal or do I need to go back to the doctor?