When I am not writing regularly I suffer from crippling self doubt. Once I open up a document and start working on it this disappears. I am able to do it with virtually no transition time. I simply do it. All my past successes count for nothing if I am not working right this moment (or have worked within 24 hours)) And the doubt extends to all other areas of my life too. My sense of self is profoundly affected. I cannot even give you good advice on getting your projects done.
I am not recommending this attitude. I am trying to change it, in fact. Let's just say that for now the solution will be to write.