Is it possible to get pregnant if you have sex the day your period starts?

Long story short... I had sex, multiple times throughout the night and none of which used a condom. He tried pulling out most of the time but I'm still worried that it wasn't done in time. While we were having sex one of the times, I started bleeding. My period was late so I was expecting it any day, just not at that time. Is it possible to get pregnant? 😣