What Causes Irregular Periods Inspite Of Being On Estelle 35 ED?

Hi,

I am on Estelle 35 ED and around Christmas I started a new pack design and accidentally started on the wrong spot (in used to one that goes round in one single line and not a wiggly line). I've now been bleeding for more than two weeks. It gets heavier and lighter heavier and lighter etc and cramps come and go. Is there a chance I've done any actual damage to my body?

Thanks