Okay, I think you might want some ways your character who has general anxiety disorder will behave. I got these basic ideas from
Anxiety Disorder Center
She will worry nearly every waking moment about imagined fears. What if my best friend dies? What if my dog is hit by a car? What if my mole is cancerous? What if a meteor hits my house?
Some fears will cause mounting panic -- breathing becomes rapid and difficult and the pulse races. She will want to run away, but doesn’t know where or in which direction.
Dreams will be nightmarish, and she may wake up in a cold sweat.
For your character’s background, this disorder may be inherited, induced by excessive alcohol and/or drugs, or from a traumatic experience.
I hope these basic thumbnail sketches help.