BLEEDING WITH IUD

Okay so I've had my IUD in for a little over 2 months. I had sex with this new guy I just started dating two weeks ago for the first time and then this past weekend. After we had sex for the first time I started spotting the next day and it has lasted till now! (Also I was bleeding a little in the beginning when I first got my IUD but it stopped like over a month ago) I don't know why I'm bleeding now. I don't have any pain and I'm confused why I keep on bleeding? Any one have the same thing or any suggestions on what is happening???