How can one overcome pathological doubt concerning creed, the Divine self, and the prophethood of Muhammad, peace be upon him, which prevents one from embracing Islam, taking into account that this doubt appears to be pathological and not a satanic whisper?

The fear of disbelief and the renewal of faith are indications of waswasah (whispers/obsessive thoughts), not of doubt that expels one from the fold of Islam. The difference between doubt that expels one from the fold of Islam and waswasah, as well as methods for treating waswasah, have been previously explained in earlier fatwas.