should I take plan b?

so I missed my pill last night & my boyfriend & I had sex but we used a condom. he finished without pulling out but the condom didn’t break. when he pulled out the condom fell off so it was still like kind of inside of me. I don’t think any sperm got inside of me bc the condom didn’t break but i’m just concerned that it fell off & that I forgot my pill last night. should I take plan b? opinions?