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

Other days

boy friend

Boy Friend Day
lisp

Lisp Day
one

One Day
promposal

Promposal Day
frozen yogurt

Frozen Yogurt Day
bow tie

Bow Tie Day
pampering

Pampering Day
my little pony

My Little Pony Day
gum

Gum Day
gallery

Gallery Day