Mirena IUD

Okay so I got my Mirena IUD about 8 1/2 weeks ago. I have not gone in for my 6 week check up because I don't have time between work and such. my doctor struggled to get it in because I have a curved cervix or whatever(never had a kid before). I am scared that I might be pregnant. My bf cummed inside me a week ago and have recently been freaking out. I am not supposed to have my normal period cycle until about another week or so. I am feeling tired(not sure if it's work) feel like I've been eating a lot more, stressed(thought of being pregnant) and kind of upset. Is this normal around the 8th week after getting your IUD? PLEASE HELP