For what it's worth, (a) I have the same bad habit, and (b) I think you made the right decision.

The only thing that works for me in regard to the self-sabotage is to break down the tasks that frighten me into manageable chunks and list them out on paper, and then check them off as I accomplish them. That way the Oh No! part of my brain can't lie to me and tell me I'm a failure; I have the documentation to prove it wrong. It also seems less inclined to balk over small tasks.

I wish you luck in finding a coping/retraining method that works for you!