Well done for trying. Not sure how far you are through the series, but it's important to keep in mind if this doesn't work out it has nothing to do with SA. As you said, they want someone with more sales experience, not someone with more experience and no social anxiety.
In the past, I would associate the huge effort required to battle my SA along with the 'failure' of what I was trying to accomplish and beat myself up for it by convincing myself that these things are just too traumatic and never work out anyway, so why bother.
The Expectations are Killers part of the series is an invaluable piece of therapy and has helped me considerably. Keep up the CBT and you will start to feel better about things as time goes on.