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

Other days

ruby

Ruby Day
fiancee

Fiancee Day
polyamory

Polyamory Day
ormille

Ormille Day
latina equal pay

Latina Equal Pay Day
book

Book Day
lisp

Lisp Day
tulip

Tulip Day
self appreciation

Self Appreciation Day
pick me

Pick Me Day