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

Other days

hoodie

Hoodie Day
boba

Boba Day
cuddle up

Cuddle Up Day
prosecco

Prosecco Day
ruby

Ruby Day
azonto is acceptable

Azonto Is Acceptable Day
aloxolt

Aloxolt Day
slime

Slime Day
bow tie

Bow Tie Day
first love

First Love Day