What Causes Delayed Periods And Why Bleeding Is Heavy On First Day?

hi,

i am a lady of 33 years married I awalysi see my Mustration period each month 3 days after the date which i saw previous month. example last month i saw my manstration period on 23rd of nov 2011 so this month i was supporse to get it on atleast 26th or 27 of Dec but instead i saw it today on 3rd of Jan 2012. and the blood for the first day is so heavy compared to the previous days.