Should I take a plan B?

I had sex with my boyfriend the other night without a condom (I know, I know. I never do this and there’s no excuse) he pulled out and finished on my stomach but I’m still super nervous and anxious and I was spotting today (my period won’t be due for a week or two). Should I take a plan B? I never have before so I don’t want to just take it and then have it mess with anything and me not be prepared either so any tips would help! It’s been just under 48 hours since we did it so I still have some time. And please no judgment, we’re adults and out of high school with office jobs and he has one college degree down and I’m halfway done with mine, it’s just not the time for a baby and we just got together. I’m just trying to be as safe as possible even after doing something stupid