for the last 4 months iv been on a higher dosage pill and it was giving me really bad symptoms so i recently (this week) started a new pill thats a lower dose. well my period started regularly on friday the 8th and i started my new pill on sunday which was the 10th starting the new pack. with the other pill i was on, my period would end on wednesday of my first week of my new pack, but now im on a lower dosage pill so its friday and my period keeps stopping and then starting and its a REALLY dark brown color, almost black. is it normal for that to happen when u change pills?