Hey there,
If you've had unprotected sex, there is a possibility that you are pregnant. However, the more urgent concern is bleeding when you're not on your period. Although there are many possible causes of this, and many of them are not serious, some of them are, and so it's important that you talk to your doctor, or another medical professional, about this. If you're not comfortable going to your doctor, you could go to a clinic like Planned Parenthood (if you're against Planned Parenthood there are sometimes other free clinics) to get free and confidential help. In the future if you're concerned about pregnancy, you could consider using a form of birth control, which you could talk to your parents or doctor about. If you really don't feel comfortable with talking to your parents and/or doctor about any of this, you can text Planned Parenthood: https://www.plannedparenthood.org/online-tools/chat. The important thing is that you talk to a real medical professional. Good luck and stay safe!