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

Other days

slime

Slime Day
my little pony

My Little Pony Day
singles

Singles Day
nail polish

Nail Polish Day
latina equal pay

Latina Equal Pay Day
bow tie

Bow Tie Day
offer

Offer Day
bonang

Bonang Day
reading

Reading Day
hoodie

Hoodie Day