Menstral Cycle Abnormally

So for the past 2 months, my period has been longer than usual... my period is usually 6-7days. last month it was 12 days & currently its been on 16 days. The blood has been mostly from bright red to dark red throughout the day.. i currently take sprintec BC pills. I’ve been taking them for 2years & have never had a problem so I don’t think its the BC.. any insight would help tremendously!