Not sure what to do

This wasn't the best choice but i decided to have unprotected sex today & the last couple weeks. Using withdrawal. I'm getting an iud in my arm tomorrow. But i know you are supposed to have protected sex to be able to get an iud, because of the possibility of becoming pregnant. I was given birth control pills but i ran out about a week ago. My last period was about 38 days ago. I was only spotting lightly on birth control pills. It stopped after i stopped taking them. But i also didn't take the birth control pills at the same time every day. It was around the same hour though. I feel fine and i don't think im pregnant. Should i get the iud anyway?