I thinking of walking out on my hookup
Why do you want to walk out on them?
My girlfriend is a jerk, a stupid bitch.
That is a terrible way to talk about a girlfriend. You should just not be in the relationship if you are not happy.
She's never understood me and I'm just not sexually into her anymore and she just won't leave me alone.
Then it is time to break up. Things didn't work out and it is good that that you realized it. End the relationship on good terms and give her a proper goodbye face to face.