Oops, it doesn't look like 'period period day' is a national day..

Other days

hoodie

Hoodie Day
china

China Day
singles

Singles Day
one

One Day
get funky

Get Funky Day
bow tie

Bow Tie Day
azonto is acceptable

Azonto Is Acceptable Day
hiv awareness

Hiv Awareness Day
ruby

Ruby Day
offer

Offer Day