Not anything you did wrong - just a miscommunication!
If you follow Gord's reply to the letter the following happens:
The formula =day(cellref) returns the day of the month - ie 20/10/0
becomes 20. If you format this to "dddd" it returns friday when toda
is actually wednesday! This is because it is just looking at 20 and ha
lost the rest of the date.
to turn a date in cell A1 into the day of the week in B1 us
=text(a1,"dddd")
if you want the day of the week as a number use =weekday(a1,1) if you
week starts on sunday, or =weekday(a1,2) if it starts on monday