I am working in the design industry for the last 7 years. I set up my studio 3 years ago and I have a steady flow of interesting clients. Every year I win at least 1 award or at least receive a nomination and I even have work published in a few magazines. Even though everything seems to be going fine, I have complete doubt. Every time I look through a design magazine or book and see the work of famous designers, I know deep down that I will never reach their stature, I will never achieve the creative excellence these designers have achieved. I am seriously doubting if it is worth to continue my profession as I will never be good enough.
You are the best judge of yourself, and if you say you are no good you must be right. Therefore take your suggestion and stop immediately. Sell the business. Get rid of the clients. Maybe keep a couple of business cards as a souvenir.