Give yourself more credit...they see something of value and are willing to pay for it, so enjoy it. If you feel you don't deserve it, then do something like take a course or go to a seminar to make it so...I remember my first payment as a consultant, and I literally laughed all the way to the bank because I felt like I got away with robbery...I got it over it almost immediately.
I felt that way teaching Thai kids ESL at small beach side Buddhist temple schools.
I'd think, "What a racket!" and hope they'd never find out I was just having fun!