Oops, it doesn't look like 'down lowtoo slow day' is a national day..

Other days

slime

Slime Day
cursing

Cursing Day
first love

First Love Day
pick me

Pick Me Day
gum

Gum Day
tulip

Tulip Day
nail polish

Nail Polish Day
hoodie

Hoodie Day
law

Law Day
kiss a brunette

Kiss A Brunette Day