Hi Machair
My experience with periods and peri was to simply expect the unexpected!
I had long ones, short ones, heavy ones, light ones, went 6 months between, then 8 days between! My longest one lasted about 37 days if I remember rightly - and only stopped when I got norethisterone from my GP.
I am post meno now but I have consulted my diary for you - here's how the last few went:
April 2010 - lasted 21 days, heavy
July 2010 - lasted 10 days, very light
October 2010 - very weedy one, only lasted 3 days
November 2010 - heaviest one ever - lasted 21 days (I do remember being confined to the loo for a few hours with this one it was so heavy

)
January 2011 - lasted 11 days but not heavy
April 2011 - lasted 10 days but not heavy
And that was it!
Hope that helps

Catweazle x