Help! I don't know if I'm overthinking or not?

Samantha

Me and my boyfriend (both 18) decided to just let him finish inside when we slept together last night without thinking it through and now I'm starting to have really bad anxiety about this and wondering if I should take plan b? He's asleep next to me as I write this, I really just don't want to risk anything and my mind is spiraling. I was supposed to start my period in a few days too. Please help!