So let's set this Millenium business straight:
The current calendar system was designed by the Roman Church to start at the birth of Jesus Christ, which of course ticks off adherents to other religions.
The first day of this calendar system was January First of the Year One: there was no Year Zero.
The First Millenium [literally 'thousand years'] ended on December 31st of the Year 1000, so the Second Millenium began the next day, on January First of the Year 1001.
The Second Millenium thus ended on December 31st of the Year 2000
. . . NOT at the end of 1999.
The Third Millenium began on January First of the Year 2001.
All the hype about celebrating the unimportant New Year's Eve ending 1999 and the New Year of 2000 was just that: more disgusting media hype.
Better you should have stayed home with your family and read a book or play Yatzee™ or Scrabble™ or some such.
New Year's Eve and Day for both 2000 and 2001 were
just
another
New Year.