One thing you can try is to charge what YOU would pay for what you consider to be an
equivalent job. Not computing, but something as valuable to you.
When you are willing to pay for the equivalent of what you want to charge then you will be able to psychologically justify to yourself and be comfortable with it. It will be in energetic integrity.
Also, try practicing saying what you want to charge to people until you can say it without flinching.
Peace and joy,
Keena