To ease my mind

I never usually let guys finish inside of me but at the beginning of this month a guy I slept with did and even though I'm on birth control I've been so scared of pregnancy ever since. I started bleeding today and it's very light and a day earlier than my usual period but am I safe to assume it's my real period and not early on pregnancy spotting? It might sound like a stupid question but if you knew how stressed I was you'd understand me asking, i just want to ease my mind lol 😅