Eleven days ago, my period ended. Yesturday it started again. It started off light then really heavy today like my periods usually are. Why has it come back. Could it be because I took four birth control pill, went to a friends for six days, left them at home and could not take them for those 6 days?

Sounds Like Exactly What It Is. 4 Bc Pills Is Too Many. You Through Off The Whole Cycle. Call Your Doc!