Having light red/dark bleeding which began 5 days before period is due and is ongoing. My breasts are extremely tender. Could I still be pregnant?

Pregnancy? Bleeding prior to a period with unprotected sex can occur with implantation of a fertilized egg, so yes, you could be pregnant. To be sure, obtain a serum HCG (quantitative) test , especially if the bleeding continues, since pregnancy outside the uterus could be the cause. If positive see your healthcare provider for an ultrasound exam and other testing.