What to do

I had sex yesterday with a condom and earlier this month my pregnancy test came up negative today but bc I did it again yesterday I’m not entirely sure. My period is scheduled for 2/26: tomorrow. Can you get ur period from having sex two days before ur start date and then still be pregnant? I’ve heard stories abt ppl like this. The only way I could be pregnant is from precum. So j wondering if I should take something to be safe. I think I’m scaring myself into things but I never know