If the condom stayed in place through ejaculation and only slipped off as you withdrew, the semen would have stayed inside the condom and the pregnancy risk is low. If it slipped off earlier during intercourse without being noticed, direct contact with semen is possible and the risk is real. Since you can't be fully sure which happened, it's safest to treat this as a genuine pregnancy risk.
Next Steps
Take an emergency contraceptive pill as soon as possible. It has been about 3 days since intercourse, so acting today matters, since these pills work best the sooner they're taken. Track your next period and take a home
pregnancy test if it is delayed by more than a week.
Health Tips
See a gynaecologist if your period doesn't arrive as expected, or if you develop heavy bleeding or pain afterward.