The pill

So ive been on the pill for a little over a year now (sprintec) and these past 3 days ive had dark brown blood when i wipe and cramped really bad the first day it happened. I really dont know whats wrong, ive never had this happen. My period is in a week and few days..

(Update)

So the old blood hasnt stopped and its been a week now and wont go away..