Janice was one of Famine's victims.
Janice was a resident of Plainville. She had begun dating Jim about a week ago. Suddenly, she became depressed over the idea that things in their lives - work, family, sleep - would constantly keep her and Jim apart.
In tears, Janice visited Jim's workplace. She accused him of choosing work over her. When Jim's co-worker Brad started making fun of her possessive behavior, Janice shot Brad in the chest, killing him.
Janice then asked what they were going to do, since prison was likely going to keep them separated. Jim came up with the idea of committing suicide in order to stay together forever. Janice and Jim aim the gun at Janice's head, and fire a shot, killing Janice. Jim shot himself soon after.
At the morgue, Sam and Dean Winchester discovered through the help of Castiel that Janice and Jim had been marked by a cupid and destined to be together. Their extreme behaviors were the result of Famine arriving in town.