Mirena and pregnancy

I'm starting to wonder if I can even get pregnant anymore. I got pregnant with my first son on birth control. Last year me and my ex fiance tried for months and never had any luck. Even know I've had a few slip ups with forgetting my birth control cus my prescription was late. The guy I was with didn't care, but nothing. I've heard a lot about the Mirena IUD causing fertility problems and I'm curious if anyone else had any problems after mirena. Not currently TTC just curious is all.