What is going on???

I have had my mirena iud for about 3 months. I am 17. I got it put in and had no problems with it until this last week. When I would check the strings in the previous months I could feel them and they felt fine but I felt a hard thing in my cervix. But I wasn't experiencing any pain or bleeding so I thought it was ok. I don't really know what it's supposed to feel like in there. I have never gotten a full on period since getting it but have had some spotting around my period times and normal cramps. This past week I have had bad cramping but not so bad that I can't move or I'm crying or anything just very uncomfortable. Last night me and my boyfriend had sex and if it was too deep, it was very painful. Afterwards I had crampy feelings and sharp pains in certain spots especially when I moved but no blood. Today being the next day, I have no crampiness but it hurts when I move and walk and use the bathroom and still no blood. What is happening? Has it moved? Is it expelling? Am I still protected from pregnancy from last night even though he never came in me? Edit, this is the next day and I have now started to bleed lightly but it's getting heavier every time I check.