What Could Cause A Long Bleeding Phase After Intake Of Pill?

Lmp:6 Feb Date of intercourse:22 Feb Pill taken on:23 Feb Effective bleeding started within a week of taking the pill..around 2 march and occured for a duration of more than two weeks. Bleeding ended in a tapering fashion on the 17th of march Usual cycle: 30 days Type of bleeding:never as heavy as the normal flow..of medium character in the initial days and slowly became low. Query:1)does my New cycle begin from the 2nd of march or after 17th? 2)what was the reason for such a long bleeding phase..could it so happen that my normal menstruation started just after the effective bleeding(due to the pill)? 3)how do I know what part of my cycle is safe now?