Did other people use this as code for 'I've got my period' when you were at school (or indeed still !), or were my school friends and I as weird as my work friend thinks we were ?!
From The Lady of Shallott - 'the mirror crack'd from side to side / 'the curse is come upon me' cried / The Lady of Shallott'
and 'the curse' being a (slightly granny-ish !) euphemism for a period.
YABU: never heard it
YANBU: I said it too