Green’s Dictionary of Slang

1. (US campus/teen) unpleasant, irritable.

1973		Eble Campus Sl. Mar. 3: rag man, rag woman – a person who is in a bad mood [...] Originally referred to the edginess that a woman exhibits during her menstrual period, when she is ‘on the rag’.
1989		P. Munro Sl. U. 156: rag 1. unhappy, crabby, nasty or bitchy female.

2. (N.Z.) no good, useless.

2003

McGill Reed Dict. of N.Z. Sl. 169: rag No good. Juvenile 1990s slang.