'Splash Pregnancy' 😨😩

My period is supposed to be here in 2 days and I seem to have all my normal PMS symptoms but I'm worried and my anxiety is extremely high. Around the end of my ovulation week, like the last day of me being fertile of the day after that different sites tell me different dates, my boyfriend and I had anal sex. According to Glow it wasn't a 'green' day but was the first day after my ovulation week. Anyways my boyfriend ejaculated inside my bum-and then obviously pulled out. He caught the sperm and cleaned me up but I'm afraid he missed some or something..what's the chance of this so called 'Splash pregnancy' where semen drips down anus and then enters vagina and causes pregnancy?😨