Girlfriend And I Had Sex With A Condom, And I

girlfriend and I had sex with a condom, and I did not ejaculate. 13 days after sex, she bleeds only for 2 or 3 min, her period is due later that week, but that night she started bleeding she was also doing things to herself, and i don't know if there was enough lubrication. Could she be pregnant or is this breakthrough bleeding?