Could I be pregnant?

I was wondering if you can get pregnant 2 days before your period is supposed to start. My ldr boyfriend and I ended up having sex in a pool while he was visiting, and he didn't cum inside me but I've been told that precum can make you pregnant. My period is one day late so far, but honestly I think its just from the stress I've had this week as I've had family visiting. What do you guys think? Is it possible that I could be pregnant?