The Thing In Her Head

Sonia's headaches have come back. They returned when she started working for the awful Harry. She'd suffered them in her youth. Whatever caused them back then seemed to have definite ideas about what she should and shouldn't do. If she tried to do something 'it' didn't like she'd get terrible jolts of pain. But if she could fight through it and make a commitment towards her future they'd stop - just as had happened when she accepted her police officer husband's proposal.
Now though that thing in her head doesn't just make it difficult for Sonia to the do what she intended, it's causing her to say and do things which are completely against her true nature. A 3, 100 word short story.