SOS: am I pregnant

So this past Monday (it’s Thursday) I an Merina iud inserted, and last week (Tuesday) I think I got my period, and I told my gyno that. I know it’s supposed to be 99% effective if it’s put in within the 7 days of ur cycle. The only problem is I am an acne med, that messes up my cycle. I had VERY light spotting (light brown) for three days the not even the week before my insertion, and had pms symptoms.

Wednesday day, so two and half days after I got it my bf and I had unprotected sex TWICE. I am scared I am pregnant, just bc we didn’t use protection for a week after it. So now I am very paranoid about it. Should I be concerned, and take a plan B? Or am I fine, I am just scared about the period thing, since it was VERY light. Should I be concerned? I know that wasn’t a smart decision on either of our ends, but it is what it is now.