if you are bleeding that heavy then you could be low on iron which unfortunatly will cause you to bleed more (i only know because im on iron meds because of it)
personally if you havent eased by monday i would get an appointment with your doctor to have that checked and he may give you something to ease it too.
i am having the same this month. i thought since af arrived on cd17 it would be light but i had light med med heavy heavy where as even on a normal cycle i would have been done or just spotting by now

our bodies are stupid!

keep us posted if you go to docs hunny
xx