From your note, you had one Depo-Provera injection and then did not repeat when you were due for your every 12 weeks or 3 month injection.
My first question is what are you using for birth control? You are no longer protected from pregnancy 12 weeks after your first injection.
It is time to make an appointment with your health care provider, or the Student Health and Counseling Center, if you are an eligible student, at 907-786-4040.
At that time you can discuss options for stopping the bleeding, and do a pregnancy check.