I Was Pregnant And Found Out That The Baby Didn't

I was pregnant and found out that the baby didn't have a heartbeat. I got a surgery and an IUD inserted at the same time. So the IUD was inserted on a Friday afternoon. It is now Thursday afternoon and I just had unprotected sex. Am I able to take plan b while having my IUD in? Just for safety's sake. And will the plan b effect further protection from my IUD?