What Causes A Heavy Period After Stopping The Contraceptive Pill?

Hi, i am on the contraceptive pill and i stopped taking it to come on my period as normal and when it came to the 5th day i started re taking the pill again as normal and gradually came off my period, however on the 3rd day of taking the pill i forgot to take it, and today i have come back on my period and its quite heavy :( I dont really know what the best thing is to do!