IUD &Plan B

I AM TERRIFIED. Me and this dude had sex and his retarted ass came in me without a warning. Well i’m on the Marina IUD and i took a plan b. I have not started my period yet i took two pregnancy test and they were negative it’s been almost a month since then and i just don’t know what to do i’m having period cramps and sore breast i’m just worried sick and i don’t wanna tell my mom so can someone please help!!