Oops, it doesn't look like 'Only Child Self Awareness day' is a national day..

Other days

self appreciation

Self Appreciation Day
prosecco

Prosecco Day
first love

First Love Day
coffee

Coffee Day
cuddle up

Cuddle Up Day
stress awareness

Stress Awareness Day
special education

Special Education Day
lumpy rug

Lumpy Rug Day
kiss a ginger

Kiss A Ginger Day
kale

Kale Day