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

Other days

hoodie

Hoodie Day
ormille

Ormille Day
nae nae

Nae Nae Day
cat girl

Cat Girl Day
mean girls

Mean Girls Day
bonang

Bonang Day
stud

Stud Day
comfy

Comfy Day
gum

Gum Day
stress awareness

Stress Awareness Day