IUD pregnancy?

I got the Skyla the beginning of November and my period lasted for a couple weeks because my uterus was getting used to it. I have had swollen and tender breasts so I figured I was starting my period. But today I had the worst cramps in the entire world. I was at the mall and I collapsed. I couldn't breathe and I couldn't walk. It would ease up so I would be walking and then it would hurt like a stabbing pain. I took a Motrin and I am laying on a heating pad but both my doctor or my OBGYN were closed so I couldn't talk to them. Should I be worried? I heard it could be an infection or and ectopic pregnancy.