someone may smell different to her all of a sudden or she is uncomfortable/in pain, (my siamese pulls his fur out when his gums hurt- who'd know- it took many years to figure this out!), and forget the swatting with newspaper. She is already upset and hitting her will make her more upset. Use spray because it doesn't hurt then reassure her that she's not in trouble but if is relentless in her pursuit, put her somewhere to cool off till she's over the inclination to attack. Did the vet fully check her out?